Mechanical Engineering MCQs
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| Mechanical Engineering Mcqs: |
| The unit of power in S.I. units is______________? |
| A. newton meter B. watt C. joule D. kilogram meter/sec E. pascal per sec |
| If two equal forces of magnitude P act at an angle 9°, their resultant will be________________? |
| A. P/2 cos 9/2 B. IP sin 9/2 C. 2P tan 9/2 D. IP cos 9/2 E. Psin 9/2 |
| Which of the following do not have identical dimensions ? |
| A. Momentum and impulse B. Torque and energy C. Torque and work D. Kinetic energy and potential energy E. Moment of a force and angular momentum |
| Which of the following is not the unit of power ? |
| A. kW (kilowatt) B. hp (horse power) C. kcal/sec D. kg m/sec E. kcal/kg sec |
| The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is as per the principle of__________________? |
| A. forces B. independence of forces C. dependence of forces D. balance of force E. resolution of forces |
| If three forces acting in different planes can be represented by a triangle, these will be in________________? |
| A. non-equilibrium B. partial equilibrium C. full equilibrium D. unpredictable E. none of the above |
| A pair of smith’s tongs is an example of the lever of__________________? |
| A. zeioth order B. first order C. second order D. third order E. fourth order |
| In the lever of third order, load W, effort P and fulcrum F are oriented as follows_________________? |
| A. W between P and F B. F between W and P C. P between W and F D. W, P and F all on one side E. none of the above |
| Which of the following is not the unit of pressure ? |
| A. kg/cm B. ata C. atmosphere D. mm of wcl E. newton |
| Hot wire anemometer is used to measure_______________? |
| A. discharge B. velocity of gas C. pressure intensity of gas D. pressure intensity of liquid |
| Which of the following is the unit of kinematic viscosity _________________? |
| A. pascal B. poise C. stoke D. faraday E. none of the above |
| Property of a fluid by which molecules of different kinds of fluids are attracted to each other is called________________? |
| A. adhesion B. cohesion C. viscosity D. compressibility E. surface tension |
| Poise is the unit of________________? |
| A. surface tension B. capillarity C. viscosity D. shear stress in fluids E. buoyancy |
| Barometer is used to measure__________________? |
| A. pressure in pipes, channels etc. B. atmospheric pressure C. very low pressure D. difference of pressure between two points E. rain level |
| Center of buoyancy is the___________________? |
| A. centroid of the displaced volume of fluid B. center of pressure of displaced volume C. e.g. of floating ‘body D. does not exist E. none of the above |
| Metacentre is the point of intersection of _________________________? |
| A. vertical upward force through e.g. of body and center line of body B. buoyant force and the center line of body C. mid point between e.g. and center of buoyancy D. all of the above E. none of the above |
| Buoyant force is___________________? |
| A. resultant force acting on a floating body B. equal to the volume of liquid displaced C. force necessary to keep a body in equilibrium D. the resultant force on a body due to the fluid surrounding it E. none of the above |
| A model of a reservior is drained in 4 mts by opening the sluice gate. The model scale is 1: 225. How long should it take to empty the prototype ? |
| A. 900 minutes B. 4 minutes C. 4 x (225)3/2 minutes D. 4 (225)1/3 minutes E. 4 x V225 minutes |
| Normal depth in open channel flow is the depth of flow corresponding to_______________? |
| A. steady flow B. unsteady flow C. laminar flow D. uniform flow E. critical flow |
| For hypersonic flow, the Mach number is___________________? |
| A. unity B. greater than unity C. greater than 2 D. greater than 4 E. greater than 10 |
| All the terms of energy in Bernoulli’s equation have dimension of_______________? |
| A. energy B. work C. mass D. length E. time |
| The fluid forces considered in the Navier Stokes equation are__________________? |
| A. gravity, pressure and viscous B. gravity, pressure and turbulent C. pressure, viscous and turbulent D. gravity, viscous and turbulent E. none of the above |
| For pipes, laminar flow occurs when Roynolds number is__________________? |
| A. less than 2000 B. between 2000 and 4000 C. more than 4000 D. less than 4000 E. none of the above |
| In a forced vortex, the velocity of flow everywhere within the fluid is__________________? |
| A. maximum B. minimum C. zero D. non-zero finite E. unpredictable |
| Adiabatic compression is one in which___________________? |
| A. temperature during compression remains constant B. no heat leaves or enters the compressor cylinder during cornpression C. temperature rise follows a linear relationship D. work done is maximum E. entropy decreases |
| The- most efficient method of compressing air is to compress it_________________? |
| A. isothermally B. adiabatically C. isentropically D. isochronically E. as per law pV |
| Isothermal compression effeicency can be attained by running the compressor__________________? |
| A. at very high speed B. at very slow speed C. at average speed D. at zero speed E. isothermally |
| Isothermal compression efficiency, even when running at high speed, can be approached by using A. multi-stage compression B. cold water spray C. both A. and B. above D. fully insulating the cylinder E. high stroke_________________? |
| Isothermal compression efficiency, even when running at high speed, can be approached by using A. multi-stage compression B. cold water spray C. both A. and B. above D. fully insulating the cylinder E. high stroke |
| The pressure and temperature conditions of air at the suction of compressor are_________________? |
| A. atmospheric B. slightly more than atmospheric C. slightly less than atmospheric D. pressure slightly more than atmospheric and temperature slightly less than atmospheric E. pressure sightly less than atmospheric and temperature slightly more than atmospheric |
| The overall isothermal eiffciency of compressor is defined as the ratio of_______________? |
| A. isothermal h.p. to the BHP of motor B. isothermal h.p. to adiabatic h.p. C. power to drive compressor to isothermal h.p. D. work to compress air isothermally to work for actual compression E. isothermal work to ideal work |
| 1 m of air at atmospheric condition weighs approximately__________________? |
| A. 0.5 kg B. 1.0 kg C. 1.3 kg D. 2.2 kg E. 3.2 kg |
| Free air is the air at________________? |
| A. atmospheric conditions at any specific location B. 20°C and 1 kg/cm2 and relative humidity of 36% C. 0°C and standard atmospheric conditions D. 15°C and 1 kg/cm2 E. 25°C, 1 kg/cm2 and relative humidity of 50%. |
| The capacity of a compressor is 5 m /mih. 5 m /min refers to_______________? |
| A. standard air B. free air C. compressed air D. compressed air at delivery pressure E. air sucked |
| Maximum work is done in compressing air when the compression is_________________? |
| A. isothermal B. adiabatic C. polytropic D. any one of the above E. none of the above |
| Standard air is the air at_____________________? |
| A. atmospheric conditions at any specific location B. 20°C and 1 kg/cm2 and relative humidity 36% C. 0°C and standard atmospheric conditions D. 15°C and 1 kg/cm2 E. 25°C, 1 kg/cm2 and RH of 60%. |
| The compressor capacity with decrease in suction temperature_________________? |
| A. increases B. decreases C. remains unaffected D. may increase or decrease depending on compressor capacity E. increases upto certain limit and then decreases |
| Inter cooling in compressors__________________? |
| A. cools the delivered air B. results in saving of power in compressing a given volume to given pressure C. is the standard practice for big compressors D. enables compression in two stages E. prevents compressor jacket running very hot |
| Isothermal compression though most efficient, but is not -practicable because_________________? |
| A. ityrequires very big cylinder B. it does not increase pressure much C. it is impossible in practice D. compressor has to run at very slow speed to achieve it E. it requires cylinder to be placed in water |
| What will be the volume of air at 327°C if its volume at 27°C is 1.5 m3/mt ? |
| A. 3 m3/mt B. 1.5 m3/mt C. 18 m3/mt D. 6 m3/mt E. 0.75 m3/mt |
| An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes________________? |
| A. one adiabatic, two isobaric, and one constant volume B. two adiabatic and two isobaric C. two adiabatic, one isobaric and one constant volume D. one adiabatic, one isobaric and two constant volume E. two isobaric, two adiabatic and one constant volume |
| The work done per unit mass of air in compression will’be least when n is equal to______________? |
| A. 1 B. 1.2 , C. 1.3 D. 1.4 E. 1.5 |
| An ideal air compressor cycle with clearance on p-v diagram can be represented by following processes_______________? |
| A. one adiabatic, two isobaric, and one constant volume B. two adiabatic and two isobaric C. two adiabatic, one isobaric and one constant volume, D. one adiabatic, one isobaric and two constant volume E. two isobaric, two adiabatic and one constant volume |
| Compression efficiency is compared against_____________________? |
| A. ideal compression B. adiabatic compression C. botii isothermal and adiabatic compression D. isentropic compression E. isothermal compression |
| Aeroplanes employ following type of compressor_______________? |
| A. radial flow B. axial flow C. centrifugal D. combination of above E. none of the above |
| Ratio of indicated H.P. and brake H.P. is known as_________________? |
| A. mechanical efficiency B. volumetric efficiency C. isothermal efficiency D. adiabatic efficiency E. relative efficiency |
| Cylinder clearance in a compressor should be _________________? |
| A. as large as possible B. as small as possible C. about 50% of swept volume D. about 100% of swept volume E. none of the above |
| Volumetric efficiency of air compressors is of the order of________________? |
| A. 20-30% B. 40-50% C. 60-70% D. 70-90% E. 90-100% |
| Volumetric efficiency of a compressor without clearance volume________________? |
| A. increases with increase in compression ratio B. decreases with increase in compression ratio C. is not dependent upon compressin ratio D. may increase/decrease depending on compressor capacity E. unpredictable |
| Volumetric efficiency is_____________________? |
| A. the ratio of stroke volume to clearance volume B. the ratio of the air actually delivered to the amount of piston displacement C. reciprocal of compression ratio D. index of compressor performance E. proportional to compression ratio |
| Ratio of compression is the ratio of__________________? |
| A. gauge discharge pressure to the gauge intake pressure B. absolute discharge pressure to the ab-solute intake pressure C. pressures at discharge and suction cor-responding to same temperature D. stroke volume and clearance volume E. none of the above |
| The ratio of work doen per cycle to the swept volume in case of compressor is called ______________? |
| A. compression index B. compression ratio C. compressor efficiency D. mean effective pressure E. compressor effectiveness |
| The net work input required for compressor with increase in clearance volume_____________________? |
| A. increases B. decreases C. remains same D. increases/decreases depending on com-pressor capacity E. unpredictable |
| Clearance volume in actual reciprocating compressors is essential __________________? |
| A. to accommedate Valves in the cylinder head B. to provide cushioning effect C. to attain high volumetric efficiency D. to avoid mechanical bang of piston with cylinder head E. to provide cushioning effect and also to avoid mechanical bang of piston with cylinder head |
| Volumetric efficiency of a compressor with clearance volume ________________? |
| A. increases with increase in compression ratio B. decreases with increase in compression ratio C. in not dependent upon compression ratio D. may increase/decrease depending on compressor capacity E. unpredictable |
| Out of the following, from where you will prefer to take intake for air compressor_________________? |
| A. from an air conditioned room maintained at 20°C B. from outside atmosphere at 1°C C. from coal yard side D. from a side where cooling tower is located nearby E. from any one of the above locations |
| Which is false statement about multistage compression ? |
| A. Power consumption per unit of air delivered is low B. Volumetric efficiency is high C. It is best suited for compression ratios around 7:1 D. The moisture in air is condensed in the intercooler E. Outlet temperature is reduced |
| Euler’s equation is applicable for__________________? |
| A. centrifugal compressor B. axial compressor C. pumps D. all of the above E. none of the above |
| Ratio of indicated h.p. to shaft h.p. in known as__________________? |
| A. compressor efficiency B. isothermal efficiency C. volumetric efficiency D. mechanical efficiency E. adiabatic efficiency |
| The clearance volume of the air compressor is kept minimum because____________________? |
| A. it allows maximum compression to be achieved B. it greatly affects volumetric efficiency C. it results in minimum work D. it permits isothermal compression E. none of the above |
| Which is false statement about air receivers ___________________? |
| A. These are used to dampen pulsations , B. These act as reservoir to- take care of sudden demands C. These increase compressor efficiency D. These knock out some oil and moisture E. These reduce frequent on/off operation of compressors |
| Rotary compressor is best suited for_____________________? |
| A. large quantity of air at high pressure B. small quantity of air at high pressure C. small quantity of air at low pressure D. large quantity of air at low pressure E. any one of the above |
| After-cooler is used to__________________? |
| A. cool the air B. decrease the delivery temperature for ease in handling C. cause moisture and oil vapour to drop out D. reduce volume E. increase pressure |
| Reciprocating air compressor is best suited for___________________? |
| A. large quantity of air at high pressure B. small quantity of air at high pressure C. small quantity of air at low pressure D. large quantity of air at low pressure E. any one of the above |
| The capacity of compressor will be highest when its intake temperature is___________________? |
| A. lowest B. highest C. anything. D. atmospheric E. none of the above |
| In multistage compressor, the isothermal compression is achieved by_________________? |
| A. employing intercooler B. by constantly cooling the cylinder C. by running compressor at very slow speed D. by insulating the cylinder E. none of the above |
| Mining industry usually employs following motive power___________________? |
| A. A.C. electric motor B. compressed air C. petrol engine D. diesel engine E. D.C. electric motor |
| Separators in compressor installations are located_____________________? |
| A. before intercooler B. after intercooler C. after receiver D. between after-cooler and air receiver E. before suction |
| An air compressor may be controlled by____________________? |
| A. throttle control B. clearance control C. blow-off control D. any one of the above E. none of the above |
| During peak load periods, the best method of controlling compressors is___________________? |
| A. start-stop motor B. constant speed unloader C. relief valve D. variable speed E. none of the above |
| The compressor performance at higher altitude compared to sea level will be _______________? |
| A. same B. higher C. lower D. dependent on other factors E. none of the above |
| A centrifugal compressor works on the principle of__________________? |
| A. conversion of pressure energy into kinetic energy B. conversion of kinetic energy into pres¬sure energy C. centripetal action D. generating pressure directly E. combination of A. and D. |
| A compressor at high altitude will draw________________? |
| A. more power B. less power C. same power D. more/less power depending on other factors E. none of the above |
| The thrust on the rotor in a centrifugal compressor is produced by________________? |
| A. radial component B. axial component C. tangential component D. resultant component |
| The area of actual indicator diagram on an air compressor as compared to area of ideal indicator diagram is_____________________? |
| A. less B. more C. same D. more/less depending on compressor capacity E. unpredictable |
| To aviod moisture troubles, the compressed air main line should __________________? |
| A. rise gradually towards the point of use B. drop gradually towards the point of use C. be laid vertically D. be laid exactly horizontally E. none of the above |
| To avoid moisture troubles, the branch connections from compressed air lines should be taken from_________________? |
| A. top side of main B. bottom side of main C. left side of main D. right side of main E. any location |
| For a compressor, least work will be done if the compression is________________ ? |
| A. isentropic B. isothermal C. polytropic D. somewhere in between isentropic and isothermal E. none of the above |
| The compressor efficiecny is the__________________? |
| A. isothermal H.P/indicated H.R B. isothermal H.P./shaft H.R C. total output/air input D. compression work/motor input E. none Of the above |
| For slow-speed large capacity compressor, following type of valve will be best suited________________? |
| A. poppet valve B. mechanical valve of the corliss, sleeve, rotary or semirotary type C. disc or feather type D. any of the above E. none of the above |
| The volumetirc efficiency of a compressor is calculated on the basis of __________________? |
| A. volume of air inhaled at working conditions B. volume of air inhaled at N.T.P. conditions C. volume at 0°C and 1 kg/cm2 D. volume at 20°C and 1 kg/cm2 E. none of the above |
| During base load operation, the best method of controlling compressor is ___________________? |
| A. start-stop motor B. constant speed unloader C. relief valve D. variable speed E. none of the above |
| The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation___________________? |
| A. 0.1% B. 0.5% C. 1.0% D. 5% E. 10%. |
| In a compressor, free air delivered is the actual volume delivered at the stated pressure reduced to ____________________? |
| A. N.T.P. conditions B. intake temperature and pressure conditions C. 0°C and 1 kg/cm2 D. 20°C and 1 kg/cm2 E. none of the above |
| The advantage of multistage compression over single stage compression is ________________? |
| A. lower power consumption per unit of air delivered B. higher volumetric efficiency C. decreased discharge temperature D. moisture free air E. all of the above |
| As the value of index ‘«’ is decreased, the volumetric efficiency will___________________? |
| A. increase B. decrease C. remain unaffected D. may increase/decrease depending on compressor clearance E. none of the above |
| The indicated work per unit mass of air delivered is___________________? |
| A. directly proportional to clearance volume B. greatly affected by clearance volume C. not affected by clearance volume D. inversely proportional to clearance volume |
| The ratio of isentropic work to Euler work is known as_____________________? |
| A. pressure coefficient B. work coefficient C. polytropic reaction D. slip factor E. compressor efficiency |
| Phenomenon of choking in compressor means __________________? |
| A. no flow of air B. fixed mass flow rate regardless of pressure ratio C. reducing mass flow rate with increase in pressure ratio D. increased inclination of chord with air steam E. does not occur |
| Diffuser in a compressor is used to _____________________? |
| A. increase velocity B. make the flow stream-line C. convert pressure energy into kinetic energy D. convert kinetic energy into pressure energy E. increase degree of reaction |
| For supplying intermittent small quantity of air at high pressure, following compressor is best suited__________________? |
| A. centrifugal B. reciprocating C. axial D. screw E. turbo jet |
| Which is false statement about advantages of multistage compressor in comparison to single stage compressor_________________? |
| A. less power requirement B. better mechanical balance C. less loss of air due to leakage past the cylinder D. more effective lubrication E. lower volumetric efficiency |
| For minimum work in multistage compression, assuming same index of compression in all stages_________________? |
| A. work done in first stage should be more B. work done in subsequent stages should increase C. work done in subsequent stages should decrease D. work done in all stages should be equal E. work done in any stage is no criterion for minimum work but depends on other factors |
| The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature__________________? |
| A. 0.1% B. 0.5% C. 1% D. 5% E. 10%. |
| The criterion of the thermodynamic efficiency for rotary compressor is_________________? |
| A. isentropic compression B. isothermal compression C. polytropic compression D. any one of the above E. none of the above |
| For a two stage compressor* if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will___________________? |
| A. increase B. decrease C. remain unaffected D. other factors control it E. unpredictable |
| Losses in a centrifugal compressor are due to__________________? |
| A. inlet losses B. impeller channel losses C. diffuser losses D. all of the above E. none of the above |
| Pick up the wrong statement about advantages of multistage compression____________________? |
| A. better lubrication is possible advantages of multistage B. more loss of air due to leakage past the cylinder C. mechanical balance is better D. air can be cooled perfectly in between E. more uniform torque, light cylinder and saving in work |
| More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than____________________? |
| A. 2 kg/cm2 B. 6 kg/cm2 C. 10 kg/cm2 D. 14.7 kg/cm2 E. none of the above |
| The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called__________________? |
| A. slip factor B. velocity factor C. velocity coefficient D. blade effectiveness |
| The ratio of isentropic work to euler’s work is known as _____________________? |
| A. compressor efficiency B. isentropic efficiency C. Euler’s efficiency D. pressure coefficient E. pressure ratio |
| The maximum compression ratio in an actual single stage axial flow comperssor is of the order of________________? |
| A. 1 : 1.2 B. 1 : 2 C. 1 : 5 D. 1 : 10 E. 1 : 1 |
| Surging is the phenomenon of___________________? |
| A. air stream blocking the passage B. motion of air at sonic velocity C. unsteady, periodic and reversed flow D. air stream not able to follow the blade contour E. production of no air pressure |
| The thermodynamic efficiency of rotary compressor is based on_______________? |
| A. isothermal compression B. adiabatic compression C. isentropic compression D. polytropic compression E. none of the above |
| Maximum delivery pressure is a rotary air compressor is of the order of__________________? |
| A. 6 kg/cm2 B. 10 kg/cm2 C. 16 kg/cm2 D. 25 kg/cm2 E. 40 kg/cm2 |
| Axial flow compressor has the following advantage over centrifugal compressor__________________? |
| A. larger air handling ability per unit frontal area B. higher pressure ratio per stage C. aerofoil blades are used D. higher average velocities E. none of the above |
| Atmospheric pressure is 1.03 kg/cm and vapour pressure is 0.03 kg/cm . The air pressure will be_____________________ ? |
| A. 1.03 kg/cm2 B. 1.06 kg/cm2 C. 1.00 kg/cm2 D. 0.53 kg/cm2 E. 0.5 kg/cm2 |
| Axial flow compressor resembles____________________ ? |
| A. centrifugal pump B. reciprocating pump C. turbine D. sliding vane compressor E. none of the above |
| The vloumetric efficiency of compressor with increase in compression ratio will ___________________? |
| A. increase B. decrease C. remain same D. may increase/decrease depending on clearance volume E. none of the above |
| The work ratio of simple gas turbine cycle depends on_________________? |
| A. pressure ratio B. maximum cycle temperature C. minimum cycle temperature D. all of the above E. none of die above |
| Open cycle gas turbine works on___________________? |
| A. Brayton or Atkinson cycle B Rankine cycle C. Carnot cycle D. Erricsson cycle E. Joule cycle |
| Gas turbines for power generaion are normally used___________________? |
| A. to supply base load requirements B. to supply peak load requirements C. to enable start thermal power plant D. in emergency E. when other sources of power fail |
| Surging phenomenon in centrifugal com-pressor depends on ___________________? |
| Pick up wrong statement ? A. mass flow rate B. pressure ratio C. change in load D. stagnation pressure at the outlet E. all of the above |
| The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called__________________? |
| A. pressure ratio B. pressure coefficient C. degree of reaction D. slip factor E. stage factor |
| Actual compression curve is___________________? |
| A. same as isothermal B. same as adiabatic C. better than isothermal and adiabatic D. in between isothermal and adiabatic E. none of the above |
| The pressure ratio of an ideal vaned compressor with increase in mass flow rate_________________? |
| A. increases B. decreases C. remains constant D. first decreases and then increases E. unpredictable |
| Gas turbine works on_______________? |
| A. Brayton or Atkinson cycle B. Carnot cycle C. Rankine cycle D. Erricsson cycle E. Joule cycle |
| Gas turbine works on______________? |
| A. Brayton or Atkinson cycle B. Carnot cycle C. Rankine cycle D. Erricsson cycle E. Joule cycle |
| Rotary compressors are suitable for ____________________? |
| A. large discharge at high pressure B. low discharge at high pressure C. large discharge at low pressure D. low discharge at low pressure E. there is no such limitation |
| The work ratio of a gas turbine plant is defined as the ratio of__________________? |
| A. net work output and heat supplied (6) net work output and work done by tur¬bine C. actual heat drop and isentropic heat drop D. net work output and isentropic heat drop E. isentropic increase/drop in tempera¬ture and actual increase/ drop in temperature |
| The pressure ratio for an open cycle gas turbine compared to closed cycle gas turbine of same h.p. is_______________? |
| A. low B. high C. same D. low/high depending on make and type E. unpredictable |
| The fuel consumption in gas turbines is accounted for by___________________? |
| A. low.er heating value B. higher heating value C. heating value D. higher calorific value E. highest calorific value |
| Mechanical efficiency of gas turbines as compared to I.C engines is____________________? |
| A. higher B. lower C. same D. depends on on odier considerations E. unpredictable |
| The air-fuel ratio in gas turbines is of the order of ______________________? |
| A. 7 : 1 B. 15 : 1 C. 30 : 1 D. 40 : 1 E. 50: 1 |
| Gas turbine blades are given a rake___________________? |
| A. equal to zero B. in the direction of motion of blades C. opposite to the direction of motion of blades D. depending on the velocity E. none of the above |
| The thermal efficiency of a gas turbine as compared to a diesel plant is__________________? |
| A. same B. more C. less D. depends on other factors E. unpredictably |
| The ratio of specific weighf/h.p. of gas turbin and I.C engines may be typically of the order of_______________________? |
| A. 1 : 1 B. 2 : 1 C. 4 : 1 D. 1:2 E. 1 : 6 |
| The pressure ratio in gas turbines is of the order of__________________? |
| A. 2:l b. 4:1 C. 61: 1 D. 9 : 1 E. 12:1. |
| Temperature of gases at end of compression as compared to exhaust gases in a gas turbine is_________________? |
| A. higher B. lower C. equal D. can’t be compared E. unpredictable |
| The hottest point in a gas turbine is______________________? |
| A. at the base B. at the tip C. in the center D. between ~ to i of the blade height E. uniformly heated |
| Efficiency of gas turbine is increased by________________ ? |
| A. reheating B. inter cooling C. adding a regenerator D. all of the above E. none of the above |
| The following is true for an open cycle gas turbine having exhaust heat exchanger. Atmospheric air before entering the compressor is____________________? |
| A. heated B. compressed air before entering the combustion chamber is heated C. bled gas from turbine is heated and readmitted for complete expansion D. exhaust gases drive the compressor E. part of exhaust gases are heated and mixed up with atmospheric air to utilise exhaust heat |
| The thermal efficiency of a simple gas turbine for a given turbine inlet temperature with increase in pressure ratio_____________________? |
| A. increases B. decreases C. first increases and then decreases D. first decreases and then increases E. remains same |
| Water gas is produced by ___________________ ? |
| A. carbonisation of coal B. passing steam over incandescent coke C. passing air and a large amount of steam over waste coal at about 65°C D. partial combustion of caol, eke, anthractie coal or charcoal in a mixed air steam blast E. same way as the natural gas |
| The combustion efficiency of a gas turbine using perfect combustion chamber is of the order of________________? |
| A. 50% B. 75% C. 85% D. 90% E. 99% |
| There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would__________________? |
| A. remain same B. decrease C. increase D. unpredictable E. none of the above |
| The ideal efficiency of simple gas turbine cycle depends on________________? |
| A. pressure ratio B. maximum cycle temperature C. minimum cycle temperature D. all of the above E. none of the above |
| The material commonly used for air craft gas turbine is__________________? |
| A. stainless steel B. high alloy’ steel C. duralumin D. Timken, Haste and Inconel allpys E. titanium |
| The jnaximum combustion pressure in gas turbine as compared to I.C. engine is_________________? |
| A. more B. less C. same D. depends on other factors E. unpredictable |
| As the turbine inlet temperature increases, the thermal efficiency of gas turbine for the optimum pressure ratio_____________________? |
| A. increases B. decreases C. remains same D. first increases and then decreases E. first decreases and then increases |
| It is not possible to use closed gas turbine cycle in aeronautical engines because_________________ ? |
| A. it is inefficient B. it is bulky C. it requires cooling water for its operation D. non of theses |
| For an irreversible gas turbine cycle, the efficiency and work ratio both depend on___________________? |
| A. pressure ratio alone B. maximum cycle temperature alone C. minimum cycle temperature alone D. both pressure ratio and maximum cycle temperature E. none of the above |
| Producer gas is produced by_____________________? |
| A. carbonisation of coal B. passing steam over incandescent coke C. passing air and a large amount of steam over waste coal at about 65°C D. partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast E. same way as the natural gas |
| A gas turbine used in air craft should have______________________? |
| A. high h.p. and low weight B. low weight and small frontal area C. small frontal area and high h.p. D. high speed and high h.p. E. all of the above |
| The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the_____________________? |
| A. adiabatic temperature drop in the stage B. total temperature drop C. total temperature drop in the stage D. total adiabaitc temperature drop E. difference of maximum and minimum temperature in the cycle |
| The closed cycle in gas turbines_________________? |
| A. provides greater flexibility B. provides lesser flexibility C. in never used D. is used when gas is to be burnt E. none of the above |
| Water is injected in gas turbine cycle to___________________? |
| A. control temperature B. control output of turbine C. control fire hazards D. increase efficiency E. it is never done |
| In the axial flow gas turbine, the work ratio is the ratio of____________________? |
| A. compressor work and turbine work B. output and input C. actual total head tempeature drop to the isentrpic total head drop from total head inlet to static head outlet D. actual compressor work and theoretical comprssor work E. none of the above |
| A closed gas turbine in which fuel is burnt directly in the air is not possible because __________________? |
| A. high pressure ratio B. increasing gas temperature C. high specific volume D. high friction losses E. paucity of 02 |
| In gas turbines^ high thermal efficiency is obtained in_________________? |
| A. closed cycle B. open cycle C. both of the above D. closed/open depending on other con-siderations E. unpredictable |
| In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of__________________? |
| A. vacuum B. atmospheric air C. compressed air D. oxygen alone E. liquid hydrogen |
| Turbo propeller has the following additional feature over the turbojet __________________? |
| A. peopeller B. diffuser C. intercooler D. turbine and combustion chamber E. starting engine |
| In jet engines, paraffin is usually used as the fuel because of its _________________? |
| A. high calorific value B. ease of atomisation C. low freezing point D. A. and C. above E. none of the above |
| If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches _________________? |
| A. isothermal B. isentropic C. adiabatic D. isochoric E. isobaric |
| Intercooling in gas turbine results in ____________________ ? |
| A. increase in net output but decrease in thermal efficiency B. increase in thermal efficiency but decrease in net output C. increase in both thermal efficiency and net output D. decrease in both thermal efficiency and net output E. none of the above |
| The power available for take off and climb in case of turbojet engine as compared to reciprocating engine is ___________________? |
| A. less B. more C. same D. may be less or more depending on ambient conditons E. unpredictable |
| Ram compression in turbojet involves____________________? |
| A. reduction of speed of incoming air and conversion of part of it into pressure energy B. compression of inlet air C. increasing speed of incoming air D. lost work E. leakage losses |
| A jet engine works on the principle of conservation of____________________? |
| A. mass B. energy C. flow D. linear momentum E. angular momentum |
| Which of the following fuels can be used in turbojet engines _____________________? |
| A. liquid hydrogne B. high speed diesel oil C. kerosene D. demethylated spirit E. methyl alcohol |
| A rocket engine for the combustion of its fuel_____________________? |
| A. carries its own oxygen B. uses surrounding air C. uses compressed atmospheric air D. does not require oxygen E. depends on electrical energy supplied by solar cells |
| Propulsive efficiency is defined as ratio of___________________? |
| A. thrust power and fuel energy B. engine output and propulsive power C. propulsive power and fuel input D. thrust power and propulsive power E. none of the above |
| In the cross compounding of the gas turbine plant__________________? |
| A. h.p. compressor L connected to h.p. turbine and l.p. compressor ot l.p. tur-bine B. h.p. compressor is connected to l.p. turbine and l.p. compressor is con-nected to h.p. turbine C. both the arrangements can be employed D. all are connected in series E. none of the above |
| A rocket works with maximum overall efficiency when air craft velocity is equal to the_________________? |
| A. jet velocity B. twice the jet velocity C. half the jet velocity D. average of the jet velocity E. no such co-relationship with jet velocity exists |
| The maximum propulsion efficiency of a turbojet is attained at around following speed __________________? |
| A. 550 km/hr B. 1050km/hr C. 1700 km/hr D. 2400km /hr E. 4000 km/hr |
| Propulsion efficiency of the following order-is obtained in practice _______________? |
| A. 34% B. 50% C. 60% D. 72% E. 85%. |
| The air entry velocity m a rocket as compared to aircraft is_________________? |
| A. same B. more C. less D. zero E. dependent on power and speed |
| In jet propulsion power unit, the inlet duct of diverging shape is used in order to _______________ ? |
| A. collect more air B. convert kinetic energy of air into pres-sure energy C. provide robust structure D. beautify the shape E. none of the above |
| The weight per horse power ratio for gas. turbine as compared to I.C. engine and steam turbine is________________? |
| A. same B. higher C. lower D. uncomparable E. unpredictable |
| The blades of gas turbine are made of_________________? |
| A. mild steel B. stainless steel C. carbon steel D. high alloy seel E. high nicket alloy (neimonic) |
| Fighter bombers use following type of engine __________________? |
| A. turbo-jet B. turbo-propeller C. rocket D. ram-jet , E. pulsojet |
| The following property is most important for material used for gas turbine blade___________________? |
| A. toughness B. fatigue C. creep D. corrosion resistance E. bulk modulus |
| The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turine and fixed higher and lower temperature) with increase in pressure ratio will___________________? |
| A. increase first at fast rate and then slow B. increase first at slow rate and then fast C. decrease continuously D. first increase, reach maximum and then decrease E. none of the above |
| The effective power of gas turbines is increased by adding the following in compressor__________________? |
| A. ammonia and water vapour B. carbon dioxide C. nitrogen D. hydrogen E. none of the above |
| Air-fuel ratio in a jet engine will be of the order of__________________? |
| A. 10: 1 B. 15: 1 C. 20 : 1 D. 60 : 1 E. 100 : |
| In jet engines the compression ratio__________________? |
| A. varies as square root of the speed B. Varies linearly to the speed C. varies as square of the speed D. varies as cube of the speed E. is constant irrespective of variation in speed |
| High air-fuel ratio is used in gas turbines______________________? |
| A. to increase the output B. to increase the efficiency C. to save fuel D. to reduce the exit temperature E. none of the above |
| In which case the air-fuel ratio is likely to be maximum _________________? |
| A. 2-stroke engine B. 4-stroke petrol engine C. 4-stroke diesef engine D. multi-cylinder engine E. gas turbine |
| Reheating in gas turbine results in___________________? |
| A. increase of work ratio B. decrease of thermal efficiency C. decrease of work ratio D. both A. and B. above E. both B. and C. above |
| Work ratio of a gas turbine may be improved by f____________________? |
| A. decreasing the compression work B. increasing the compression work C. increasing the turbine work D. decreasing the turbine work E. A. and C. above |
| In the aircraft propellers __________________? |
| A. the propulsive matter is caused to flow around the propelled body B. propulsive matter is ejected from within the propelled body C. its functioning does not depend on presence of air D. all of the above E. none of the above |
| Work ratio of a gas turbine plant is ratio of______________________? |
| A. net work output and work done by turbine B. net work output and heat supplied C. work done by turbine and heat supplied D. work done by turbine and net work output E. actual/heat drop and isentropic heat drop |
| The main purpose of reheating in gas turbine is to__________________? |
| A. increase temperature B. reduce turbine size C. increase power output D. increase speed E. increase pressure ratio |
| Gas turbine cycle with Regenerator __________________? |
| A. increases thermal efficiency B. allows high compression ratio C. decreases heat loss is exhaust D. allows operation at very high altitudes E. permits high moisture content fuel to be used |
| Reheating in multistage expansion gas turbine results in____________________? |
| A. high thermal efficiency B. reduction in compressor work C. decrease of heat loss in exhaust D. maximum work output E. none of the above |
| Maximum temprature in a gas turbine is of the order of COMPRESSORS, GAS TURBINES AND JET ENGINES______________________? |
| A. 2500°C B. 2000°C C. 1500°C D. 1000°C E. 700°C |
| In air breathing jet engine, the jet is formed by expanding__________________? |
| A. gases B. solids C. liquid D. plasma E. highly heated atmospheric air |
| The efficiency of jet engine is__________________? |
| A. higher at ground B. higher at high altitudes C. same at all altitudes D. higher at high speed E. lower at low speed |
| For speed above 3000 km/hour, it is more advantageous to use____________________? |
| A. turbo-jet engine B. ram-jet engine C. propellers D. rockets E. hydraulic jet propulsion |
| The compression ratio in a jet engine varies proportional to ____________________? |
| A. speed B. speed C. altitude D. Vspeed E. does not Vary |
| The efficiency and work ratio of a gas turbine plant can be increased by _____________________? |
| A. using mulit-stage compressor with mfercooler B. adding heat exchanger C. injecting water in/around combustion chamber D. reheating the air after partial expansion in the turbine E. all of the above |
| Turbofan engine employs ____________________ ? |
| A. one air stream B. two or more air streams C. no air stream D. solid fuel firing E. rocket principle for its operation |
| Which of the following plants is smallest and lightest for genrating a given amount of power__________________? |
| A. steam power plant B. petrol engine C. diesel engine’ D. solar plant E. gas turbine plant |
| Pressure ratio in gas turbines is the ratio of ____________________? |
| A. compressor pressure ratio B. highest pressure to exhaust pressure C. inlet pressure to exhaust pressure D. pressures across the turbine E. none of the above |
| In turbo fan engine, the jet velocity as compared to turbo-jet engine is_________________? |
| A. less B. more C. same D. may be less or more depening upon speed E. none of the above |
| A simple turbo-jet engine is basically_________________? |
| A. a propeller system B. gas-turbine engine equipped with a propulsive nozzle and diffuse* C. chemical rocket regine D. ram-jet enigne E. none of the above |
| Ram-jet engine__________________? |
| A. is self-operating at zero flight speed B. is not self-operating at zero^flight speed C. requires no air for its operation D. produces a jet consisting of plasma E. none of the above |
| The compression ratio in a gas turbine is of the roder of____________________? |
| A. 3.5 : 1 B. 5 : 1 C. 8 : 1 D. 12 : 1 E. 20 : 1 |
| The working fluid in ai turbine is___________________? |
| A. in two phases B. in three phases C. in a single phase D. in the form of air and water mixture E. gas and no air |
| If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix i and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity______________? |
| A. Vi=V0B B. Vt>V0 C. U,<V0 D. V,= U0 E. Vri=Vm |
| In jet engines the products of combustion after passing through the gas lurbine are discharged into_______________? |
| A. atmosphere B. back to the compressor C. discharge nozzle D. vacuum E. none of the above |
| A file removes the metal during___________________? |
| A. both forward and return strokes B. forward stroke C. return stroke D. none of these |
| In a _____________ , both cutting and non-cutting operations are performed at one station of the press in every stroke of the ram? |
| A. progressive die B. simple die C. compound die D. combination die |
| A neutral flame is obtained by supplying___________________? |
| A. more volume of acetylene and less volume of oxygen B. equal volumes of oxygen and acetylene C. more volume of oxygen and less volume of acetylene D. none of the above |
| The cold working of metals is carried out_________________? |
| A. below the recrystallisation temperature B. at the recrystallisation temperature C. at any temperature D. above the recrystallisation temperature |
| Lancing is the operation of _________________? |
| A. cutting a sheet of metal through part of its length and then bending the cut portion B. removal of metal to the desired shape from the edge of a plate C. cutting a sheet of metal in a straight line along the length D. bending a sheet of metal along a curved axis |
| In spot welding, the spacing between two spot weld should not be less than _______________? |
| A. d B. 1.5d C. 3d D. 6d |
| The shrinkage allowance for cast iron pattern is________________? |
| A. 15 mm/m B. 20 mm/m C. 26 mm/m D. 10 mm/m |
| Tandem drawing of wires and tubes is necessary because_________________? |
| A. accuracy in dimensions is not possible otherwise B. surface finish improves after every drawing stage C. it is not possible to reduce at one stage D. annealing is needed between stages |
| The operation of straightening a curved sheet metal, is known as____________________? |
| A. squeezing B. coining C. planishing D. drawing |
| For starting an axial flow pump, its delivery valve should be____________________? |
| A. closed B. open C. depends on starting condition and flow desired D. could be either open or closed E. partly open and partly closed |
| Centrifugal pump is started with its delivery valve __________________? |
| A. kept fully closed B. kept fully open C. irrespective of any position D. kept 50% open E. none of the above |
| When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be _________________? |
| A. horizontal B. nearly horizontal C. steep D. first rise and then fall E. none of the above |
| Multistage centrifugal pumps are used to obtain___________________? |
| A. high discharge B. high head C. pumping of viscous fluids D. high head and high discharge E. high efficiency |
| In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by_______________? |
| A. designing new impeller B. trimming the impeller size to the required size by machining C. not possible D. some other alterations in the impeller E. none of the above |
| One horsepower is equal to_________________? |
| A. 102 watts B. 75 watts C. 550 watts D. 736 watts E. 33000 watts |
| Axial flow pump is started with its delivery valve________________? |
| A. kept fully closed B. kept fully open C. irrespective of any position D. kept 50% open E. none of the above |
| Head developed by a centrifugal pump depends on___________________? |
| A. impeller diameter B. speed C. fluid density D. type of casing E. A. and B. above |
| In a centrifugal pump casing, the flow of water leaving the_______________? |
| A. radial B. radial C. centrifugal D. rectilinear E. vortex |
| Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of____________________? |
| A. high initial and maintenance cost B. lower discharge C. lower speed of operation D. necessity of air vessel E. all of the above |
| The efficiency of a centrifugal pump is maximum when its blades are__________________? |
| A. straight B. bent forward C. bent backward D. bent forward first and then backward E. bent backward first and then forward |
| When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be__________________? |
| A. horizontal B. nearly horizontal C. steep D. first rise and then fall E. none of the above |
| If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge_____________________? |
| A. same quantity of liquid B. 0.75 Q C. Q/0.75 D. 1.5 Q E. none of the above |
| The optimum value of vane exit angle for a centrifugal pump impeller is_________________? |
| A. 10-15° B. 20-25° C. 30-40° D. 50-60° E. 80-90°. |
| In centrifugal pumps, maximum efficiency is obtained when the blades are_________________? |
| A. straight B. bent forward C. bent backward D. radial E. given aerofoil section |
| In a centrifugal pump, the liquid enters the pump__________________? |
| A. at the top B. at the bottom C. at the center D. from sides E. none of the above |
| Low specific speed of a pump implies it is____________________? |
| A. centrifugal pump B. mixed flow pump C. axial flow pump D. any one of the above E. none of the above |
| For small discharge at high pressure, following pump is preferred_____________________? |
| A. centrifugal B. axial flow C. mixed flow D. propeller E. reciprocating |
| The horse power required in above case will be___________________? |
| A. same B. 0.75 B.H.P. C. B.H.P./0.75 D. 1.5 B.H.P. E. none of the above |
| Motion of a liquid in a volute casing of a centrifugal pump is an example of____________________? |
| A. rotational flow B. radial C. forced spiral vortex flow D. forced cylindrical vortex flow E. spiral vortex flow |
| Medium specific speed of a pump implies it is_________________? |
| A. centrifugal pump B. mixed flow pump C. axial flow pump D. any one of the above E. none of the above |
| Indicator diagram of a reciprocating pump is a graph between________________? |
| A. flow vs swept volume B. pressure in cylinder vs swept volume C. flow vs speed D. pressure vs speed E. swept volume vs speed |
| Any change in load is adjusted by adjusting following parameter on turbine______________? |
| A. net head B. absolute velocity C. blade velocity D. flow E. relative velocity of flow at inlet |
| The maximum number of jets generally employed in impulse turbine without jet interference is________________? |
| A. 4 B. 6 C. 8 D. 12 E. 16. |
| High specific speed of turbine implies it is__________________? |
| A. propeller turbine B. Francis turbine C. impulse turbine D. any one of the above E. none of the above |
| Casting of a centrifugal pump is designed so as to minimize________________? |
| A. friction loss B. cavitation C. static head D. loss of kinetic energy E. starting time |
| Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between_________________? |
| A. lift and resultant force B. drag and resultant force C. lift and tangential force D. lift and drag E. resultant force and tangential force |
| The flow rate in gear pump___________________? |
| A. increases with increase in pressure B. decreases with increase in pressure C. more or less remains constant with in-crease in pressure D. unpredictable E. none of the above |
| Reaction turbines are used for____________________? |
| A. low head B. high head C. high head and low discharge D. high head and high discharge E. low head and high discharge |
| The angle of taper on draft tube is A. greater than 15° B. greater than 8° C. greater than 5° D. less than 8° E. less than 3°.___________________? |
| The angle of taper on draft tube is A. greater than 15° B. greater than 8° C. greater than 5° D. less than 8° E. less than 3°. |
| In axial flow fans and turbines, fluid enters and leaves as follows________________? |
| A. radially, axially B. axially, radially C. axially, axially D. radially, radially E. combination of axial and radial |
| Air vessels in reciprocating pump are used to__________________? |
| A. smoothen flow B. reduce acceleration to minimum C. increase pump efficiency D. save pump from cavitation E. increase pump head |
| According to fan laws, at constant speed and capacity, the pressure and power vary_____________________? |
| A. directly as the air or gas density B. inversely as square root of density C. inversely as density D. as square of density E. as square root of density |
| Maximum impulse will be developed in hydraulic ram when ___________________? |
| A. waste valve closes suddenly B. supply pipe is long C. supply pipe is short D. ram chamber is large E. supply pipe has critical diameter |
| A hydraulic intensifier normally consists of __________________? |
| A. two cylinders, two rams and a storage device B. a cylinder and a ram C. two co-axial rams and two cylinders D. a cylinder, a piston, storage tank and control valve E. special type of pump with storage device and a pressure regulator |
| Hydraulic accumulator is used for____________________? |
| A. accumulating oil B. supplying large quantities of oil for very short duration C. generally high pressures to operate hydraulic machines D. supplying energy when main supply fails E. accumulating hydraulic energy |
| Puck up the wrong statement about centrifugal pump_______________? |
| A. discharge a diameter B. head a speed2 C. head a diameter D. Power a speed3 E. none of the above is wrong |
| Saving of work done and power by fitting an air vessel to double acting reciprocating pump is of the order of_______________? |
| A. 39.2% B. 49.2% C. 68.8% D. 84.8% E. 91.6%. |
| A hydraulic accumulator normally consists of________________? |
| A. two cylinders, two rams and a storage device B. a cylinder and a ram C. two co-axial rams and two cylinders D. a cylinder, a piston, storage tank and control valve E. special type of pump with storage device and a pressure regulator |
| According to fan laws, at constant weight of air or gas, the speed, capacity and pressure vary________________? |
| A. directly as the air or gas density B. inversely as square root of density C. inversely as density D. as square of density E. as square root of density |
| According to fan laws, for the fans having constant wheel diameters, the power demand varies_______________? |
| A. directly as fan speed B. square of fan speed C. cube of fan speed D. square root of fan speed E. none of the above |
| According to fan laws, at constant pressure, the speed capacity and power vary_________________? |
| A. directly as the air or gas density B. inversely as square root of density C. inversely as density D. as square of density E. as square root of density |
| Pressure intensifier increases the pressure in proportion to____________________? |
| A. ratio of diameters B. square of ratio of diameters C. inverse ratio of diameters D. square of inverse ratio of diameters E. fourth power of ratio of diameters |
| According to fan laws, for fans having constant wheel diameter, the pressure varies________________? |
| A. directly as fan speed B. square of fan speed C. cube of fan speed D. square root of fan speed E. none of the above |
| Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of__________________? |
| A. 39.2% B. 49.2% C. 68.8% D. 84.8% E. 91.6%. |
| According to fan laws, for fans having constant wheel diameter, the air or gas capacity varies______________________? |
| A. directly as fan speed B. square of fan speed C. cube of fan speed D. square root of fan speed E. none of the above |
| Which place in hydraulic turbine is most susceptible for cavitation __________________? |
| A. inlet of draft rube B. blade inlet C. guide blade D. penstock E. draft tube exit |
| Specific speed for reaction turbines ranges from___________________? |
| A. 0 to 4.5 B. 10 to 100 C. 80 to 200 D. 250 to 300 E. none of the above |
| The discharge through a reaction turbine with increase in unit speed____________________? |
| A. increases B. decreases C. remains unaffected D. first increases and then decreases E. first decreases and then increases |
| Francis, Kaplan and propeller turbines fall under the category of___________________? |
| A. Impulse turbines B. Reaction turbines C. Axial flow turbines D. Mixed flow turbines E. Reaction-cum-impulse turbines |
| Francis turbine is best suited for_____________________? |
| A. medium head application from 24 to 180 m B. low head installation up to 30 m C. high head installation above 180 m D. all types of heads E. none of the above |
| Impulse turbine is generally fitted______________________? |
| A. at the level of tail race B. little above the tail race C. slightly below the tail race D. about 2.5 m above the tail race to avoid cavitation E. about 2.5 m below the tail race to avoid cavitation |
| In reaction turbine, draft tube is used_____________________? |
| A. to transport water downstream without eddies B. to convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section C. for safety of turbine D. to increase flow rate E. none of the above |
| A turbine pump is basically a centrifugal pump equipped additionally with_________________? |
| A. adjustable blades B. backward curved blades C. vaned diffusion casing D. inlet guide blades E. totally submerged operation facility |
| The specific speed of turbine is defined as the speed of a unit___________________? |
| A. of such a size that it delivers unit dis-charge at unit head B. of such a size that it delivers unit dis-charge at unit power C. of such a size that it requires unit power per unit head D. of such a size that it produces unit horse power with unit head E. none of the above |
| Medium specific speea of turbine implies it is___________________? |
| A. propeller turbine B. Francis turbine C. impulse turbine D. any one of the above E. none of the above |
| Runaway speed of a hydraulic turbine is_________________? |
| A. full load speed B. the speed at which turbine runner will be damaged C. the speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open D. the speed corresponding to maximum overload permissible E. none of the above. |
| Low specific speed of turbine implies it is__________________? |
| A. propeller turbine B. Francis turbine C. impulse turbine D. any one of the above E. none of the above |
| High specific speed of a pump implies it is_____________________? |
| A. centrifugal pump B. mixed flow pump C. axial flow pump D. any one of the above E. none of the above |
| For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred_________________? |
| A. centrifugal B. axial flow C. reciprocating D. mixed flow E. none of the above |
| In a centrifugal pump casing, the flow of water leaving the impeller, is___________________? |
| A. rectilinear flow B. radial flow C. free vortex motion D. forced vortex E. none of the above |
| Atomic number of an element in the periodic table represents the numbers of_________________? |
| A. protons in the nucleus B. electrons in me nucleus C. neutrons in the nucleus D. electrons in the atom E. neutrons in the atom |
| Which is not identical for an atom and an isotope_________________? |
| A. mass number B. atomic number C. chemical properties D. position in periodic table E. all of the above |
| A nuclear unit becoming critical means_______________? |
| A. it is generating power to rated capacity B. it is capable of generating much more than rated capacity C. there is danger of nuclear spread D. chain reaction that causes automatic splitting of the fuel nuclei has been established E. it generates no heat |
| The total energy released in fission of U is__________________? |
| A. 5 MeV B. 10 MeV C. 199 MeV D. 168 MeV E. 11 MeV |
| Boiling water reactor employs__________________? |
| A. boiler B. direct cycle of coolant system C. double circuit system of coolant cycle D. multi pass system E. single circuit system |
| One gram of uranium will produce energy equivalent to approximately____________________? |
| A. 1 tonne of high grade coal B. 4.5 tonnes of high grade coal C. 10 tonnes of high grade coal D. 100 tonnes of high grade coal E. 1000 tonnes of high grade coal |
| Breeder reactor has a conversion ratio of_____________________? |
| A. unity B. more than unity C. less than unity D. zero E. infinity |
| Fast breeder reactor uses___________________? |
| A. boiler B. direct cycle of coolant system C. double circuit system of coolant cycle D. multi pass system E. single circuit system |
| Which of the following nuclear reactor does not need a heat exchanger for generation of steam____________________? |
| A. gas cooled B. liquid metal cooled C. pressurised water D. boiling water E. none of the above |
| The efficiency of a nuclear power plant in comparsion to a conventional thermal power plant is________________? |
| A. same B. more C. less D. may be less or mote depending on size E. unpredictable |
| Isotopes of same elements have___________________? |
| A. same atomic number and different masses B. same chemical properties but different atomic numbers C. different masses and different atomic numbers D. different chemical properties and same atomic numbers E. same chemical properties and same atomic numbers |
| Amongst the following, the fissionable materials are________________? |
| A. U233andPu239 B. U23iandPu233 C. U235andPu235 D. U238andPu239 E. U243andPu235 |
| The nuclear energy is measured as__________________? |
| A. MeV B. curie C. farads D. MW E. kWhr |
| Moderator in nuclear plants is used to__________________? |
| A. reduce temperature B. extract heat from nuclear reaction C. control the reaction D. cause collision with the fast moving neutrons to reduce their speed E. moderate the radioactive pollution |
| The most commonly used moderator in nuclear plants is___________________? |
| A. heavy water B. concrete and bricks C. graphite and concrete D. deutrium E. graphite |
| The main interest of shielding in nuclear reactor is protection against_______________? |
| A. X-rays B. infra-red rays C. a, P, and y rays D. neutrons and gamma rays E. electrons |
| Which of the following are ferrite materials__________________? |
| A. U233andPu239 B. U C. U238andPu239 D. U238andTh239 E. none of the above |
| Enriched uranium is one in which__________________? |
| A. %age of U235 has been artificially in-creased B. %age of U has been artificially increased C. %age of U234 has been artificially in-creased D. extra energy is pumped from outside E. all impurities have been removed |
| Which of the following is the heaviest________________? |
| A. neutron B. proton C. atom D. electron E. nucleus |
| The breeding gain in case of thermal breeder reactor as compared to fast breeder reactor is________________? |
| A. same B. lower C. higher D. unity E. higher/lower depending on the size of reactor |
| A nuclear fission produces energy of following order in MeV___________________? |
| A. 20 B. 200 C. 2000 D. 20,000 E. 2 x 105 |
| The process by which a heavy nucleus is splitted into two light nuclei is known as_________________? |
| A. splitting B. fission C. fusion D. disintegration E. chain reaction |
| The fast breeder reactor uses the following moderator__________________? |
| A. demineralised water B. carbon dioxide C. heavy water D. graphite E. no moderator is used |
| The mass number of a substance represents the sum of total number of___________________? |
| A. protons and neutrons in an atom B. protons and electrons in an atom C. neutrons and electrons in an atom D. protons and neutrons in a nucleus E. protons and electrons in a nucleus |
| A nuclear fission is initiated when the critical energy as compared to neutron binding energy of the atoms is_________________? |
| A. same B. more C. less D. there is no such criterion E. none of the above |
| Gas cooled reactor uses following materials as moderator, and coolant____________________? |
| A. graphite, C02 B. graphite, air C. heavy water, C02 D. lead, H2 E. concrete, N2 |
| In nuclear fission each neutron that causes fission releases_______________? |
| A. no new neutron B. at least one new neutron C. one new neutron D. more than one new neutrons E. many-fold neutrons |
| Which of the following particles is the lightest__________________? |
| A. nucleus B. electron C. proton D. meson E. neutron |
| In fast breeder reactors___________________? |
| A. any type of moderator can be used B. graphite is used as the moderator C. heavy water is used as the moderator D. moderator may or may not be used E. moderator is dispensed with |
| Ferrite material is____________________? |
| A. the most fissionable material B. the basic fuel for nuclear paints C. basic raw material for nuclear plants D. the material which absorbs neutrons and undergoes spontaneous changes leading to the formation of fissionable material E. none of the above |
| The energy required to be applied to a radioactive nucleus for the emission of a neutron is________________? |
| A. 1 MeV B. 2.4 MeV C. 4.3 MeV D. 7.8 MeV E. 20 MeV |
| The commonly used material for shielding is__________________? |
| A. lead or concrete B. lead and tin C. graphite or cadmium D. thick galvanised sheets E. black carbon papers |
| Reflector in nuclear plants is used to________________? |
| A. return the neutrons back into the core B. shield the radioactivity completely C. check polllution D. conserve energy E. is not used |
| The number of isotopes of hydrogen are _________________? |
| A. 1 B. 2 C. U C. 3 E. 0 |
| The nuclear power plant at Tarapur has the following reactor________________? |
| A. fast breeder B. pressurised water C. boiling water D. sodium graphite E. none of the above |
| Ideally the neutron flux in reactor should be__________________ ? |
| A. maximum in center and zero at side B. maximum at side and zero in center C. uniform throughout D. zero throughout E. none of the above |
| U238 will undergo fission by_________________? |
| A. high energy (fast) neutrons alone B. low energy (slow) neutrons alone C. either fast or slow neutrons D. medium energy neutrons E. none of the above |
| Boiling water reactor uses the following as moderator, coolant and working fluid________________? |
| A. ordinary fluid B. heavy water C. molten lead D. hydrogen gas E. none of the above |
| The first unclear power plant in India is located at____________________? |
| A. Kota B. Kalapakkam C. Tarapur D. Baraeilly E. Kerala |
| U235 will undergo fission by__________________? |
| A. high energy (fast) neutrons alone B. low energy (slow) neutrons alone C. either fast or slow neutrons D. medium energy neutrons E. none of the above |
| Hydrogen is preferred as better coolant in comparison to C02 because former_____________________? |
| A. is lighter B. is inert C. has high specific heat D. is a good conductor E. all of the above |
| The risk of radioactive hazard is greatest in the turbine with following reactor___________________? |
| A. pressurised water B. boiling water C. gas cooled D. liquid metal cooled E. all of the above. |
| Electron-volt is the unit of________________? |
| A. atomic power B. energy C. voltage D. radio activity E. there is no such unit. |
| A reactor capable of converting a ferrite material into fissile isotopes is called____________________? |
| A. regenerative reactor B. fast breeder reactor C. breeder reactor D. boiling water reactor E. ferrite reactor |
| Enriched uranium may contain fissionable contents of the order of__________________? |
| A. 1-99% B. 1-25% C. 1-50% D. 1-75% E. 1-90%. |
| Natural uranium is made up of__________________? |
| A. 99.282% U238, 0.712% U235, 0.006% U234 B. 99.282% U235, 0.712% U238, 0.06%’ U234 C. 99.282% U234, 0.712% U238, 0.006% U235 D. 99.282% U235, 0.712% U234, 0.006% U238 E. none of the above |
| Plutonium is produced________________? |
| A. as basic raw material B. by neutron irradiation of Uz C. by neutron irradiation of throium D. artificially E. in high capacity furnace |
| Uranium-233 is produced__________________? |
| A. as basic raw material B. by neutron irradiation of Uz C. by neutron irradiation of thorium D. artificially E. in high capacity furnaces |
| The unit of radio-activity is_____________? |
| A. electron-volt B. electron-ampere C. curie D. MeV E. AMU |
| Pick up the wrong statement Fast breeder reactors__________________? |
| A. operate at extremely high power densities. B. are liquid-metal cooled C. produce more fuel than they consume D. are unmoderated E. use water as coolant |
| Plutonium-239 is produced__________________? |
| A. as basic raw material B. by neutron irradiation of IT* C. by neutron irradiation of thorium D. artificially E. in high capacity furnaces |
| Which of the following is the primary fuel________________? |
| A. Ulii B. U C. U238 D. Pu: E. Pu |
| Which of the following can be used as a coolant in nuclear plant________________? |
| A. light or heavy water B. molten lead C. carbon dioxide D. freon E. carbon tetrachloride |
| In the breeder reactors the generation of new fissionable atom is_________________? |
| A. at the lower rate than the consumption B. at a higher rate than the constuption C. at an equal rate of the consumption D. depends on other considerations E. unpredictable |
| When a reactor becomes critical, then the production of neutrons is_________________? |
| A. infinite B. zero C. exactly balanced by the loss of neutrons through leakage D. initiated E. stopped |
| Reactors designed for propulsion applications are designed for_______________? |
| A. natural uranium B. enriched uranium C. pure uranium D. any type of uranium E. none of the above |
| Solid- fuel for nuclear reactions may be fabricated into various small shapes such as___________________? |
| A. plates B. pallets C. pins D. any one of the above E. none of the above |
| Which of the following is more appropriate for a moderator. One which_________________? |
| A. does not absorb neutrons B. absorbs neutrons C. accelerates neutrons D. eats up neutrons E. regenerates neutrons |
| In triggering fission, the following types of neutrons are desirable_________________? |
| A. fast moving B. slow moving C. critical neutrons D. neutrons at rest E. none of the above |
| In a fission process, maximum %age of energy is released as___________________? |
| A. kinetic energy of neutrons B. kinetic energy of fission products C. instantaneous release of gamma rays D. gradual readioactive decay of fission products E. none of the above |
| The following present serious difficulty in designing reactor shield_________________? |
| A. alpha particles B. beta particles C. thermal neutrons D. fast neutrons and gamma rays E. none of the above |
| In order to have constant clain reaction to produce a constant rate of heat output, the value of ratio of the number of neutrons in one generation to the number of neutrons in the immediately preceding generation must be________________? |
| A. greater than 1.0 B. less than 1.0 C. equal to zero D. equal to 1.0 E. equal to infinity |
| A fission chain reaction in uranium can be developed by________________? |
| A. slowing down fast neutrons so that Uz fission continues by slow motion neutrons B. accelerating fast neutrons C. absorbing all neutrons D. using moderator E. enriching U235 |
| The fuel needed, with reflector in nuclear power plant, in order to generate sufficient neutrons to sustain a chain reaction, would be________________? |
| A. more B. less C. same D. zero E. negative, i.e. fuel would be generated |
| The efficiency of a nuclear power plant in comparison to conventional and nuclear consideration is__________________? |
| A. higher cost of nuclear fuel B. high initial cost C. high heat rejection in condenser D. lower temperature and pressure condi-tions E. nuclear hazard risk |
| The presence of reflector in nuclear power plants results in___________________? |
| A. increased production of neutrons B. complete absorption of neutrons C. controlled production of neutrons D. decreased leakage of neutrons E. decrease of speed of neutrons |
| The most practical fuel for a thermo-nuclear reactor, both from econocical and nuclear consideration is____________________? |
| A. plutonium B. uranium C. deuterium D. thorium E. lithium |
| The coolant used in boiling water reactor is________________? |
| A. Co2 B. pressurised water C. mixture of water and steam D. liquid metal E. mercury |
| Effective moderators are those materials which contain____________________? |
| A. light weight atoms B. heavy weight atoms C. critical atoms D. zero weight atoms E. there is no such criterion |
| A fast breeder reactor uses_______________? |
| A. 90% U-235 B. U-238 C. U-235 D. Pu-239 E. U-239 |
| Pressurised water reactor is designed________________? |
| A. for boiling pi water in the core B. to use liquid sodium metal as coolant C. to use intermediate coolant D. to prevent the water coolant from boiling in the core E. to eliminate the coolant loop of the pressurised water |
| In boiling water reactor, moderator is__________________? |
| A. coolant itself B. ferrite rod C. graphite rod D. liquid sodium metal E. blanket of thorium |
| Half life of a radioactive isotope corresponds to the time required for half of the following to decay__________________? |
| A. electrons B. protons C. neutrons D. nulceus E. atom |
| Artificial radioactive isotopes find application in________________? |
| A. power generation B. nucleonic devices C. nuclear fission D. nuclear fusion E. medical field |
| A fast breeder reactor uses following as fuel_________________? |
| A. enriched uranium B. plutonium C. thorium D. U235 E. natrual uranium |
| A fast breeder reactor__________________? |
| A. uses graphite rods as moderator B. has powerful moderator C. has no moderator D. uses ferrite material as moderator E. uses pressurised water as moderator |
| Each fission of U235 produces following number of fast neutrons per fission________________? |
| A. 1 neutron B. 1 — neutrons C. 1 – 2 neutrons D. 2 — neutrons E. infinite |
| For economical operation of a nuclear plant__________________? |
| A. used fuel should be reprocessed B. moderator should be used C. coolant should be employed D. control rods should be used E. reflector should be used |
| In nuclear fission___________________? |
| A. the original elements change into completely different elements B. the electrons of the element change C. the molecules rearrange themselves to form other molecules D. none of the above |
| A boiling water reactor uses following as fuel________________? |
| A. enriched uranium B. plutonium C. thorium D. U E. natural uranium. |
| Which of the following type of pump is used in liquid metal cooled reactor for circulation of liquid metal_________________? |
| A. centrifugal B. axial C. reciprocation D. electromagnetic E. diaphragm |
| Heat transfer takes place as per ________________? |
| A. zeroth law of thermodynamics B. first law of thermodynamic C. second law of the thermodynamics D. Kirchoff’s law E. Stefan’s law |
| When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by __________________? |
| A. conduction B. convection C. radiation D. conduction and convection E. convection and radiation |
| Heat is closely related with___________________? |
| A. liquids B. energy C. temperature D. entropy E. enthalpy |
| The insulation ability of an insulator with the presence of moisture would_________________? |
| A. increase B. decrease C. remain unaffected D. may increase/decrease depending on temperature and thickness of insulation E. none of the above |
| Thermal conductivity of non-metallic amorphous solids with decrease in temperature __________________? |
| A. increases B. decreases C. remains constant D. may increase or decrease depending on temperature E. unpredictable |
| Unit of thermal conductivity in M.K.S. units is ___________________? |
| A. kcal/kg m2 °C B. kcal-m/hr m2 °C C. kcal/hr m2 °C D. kcal-m/hr °C E. kcal-m/m2 °C |
| When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by ___________________? |
| A. conduction B. convection C. radiation D. conduction and convection E. convection and radiation |
| Thermal conductivity of solid metals with rise in temperature normally___________________? |
| A. increases B. decreases C. remains constant D. may increase or decrease depending on temperature E. unpredictable |
| Sensible heat is the heat required to __________________? |
| A. change vapour into liquid B. change liquid into vapour C. increase the temperature of a liquid of vapour D. convert water into steam and superheat it E. convert saturated steam into dry steam |
| When heat is Transferred by molecular collision, it is referred to as heat transfer by __________________? |
| A. conduction B. convection C. radiation D. scattering E. convection and radiation |
| Unit of thermal conductivity in S.I. units is__________________? |
| A. J/m2 sec B. J/m °K sec C. W/m °K D. A. and C. above E. B. and C. above |
| Heat transfer in liquid and gases takes place by_____________________? |
| A. conduction B. convection C. radiation D. conduction and convection E. convection and radiation |
| Heat flowing from one side to other depends directly on ___________________? |
| Pick up the wrong case? |
| A. face area B. time C. thickness D. temperature difference E. thermal conductivity |
| Which of the following is the case of heat transfer by radiation ___________________? |
| A. blast furnace B. heating of building C. cooling of parts in furnace D. heat received by a person from fireplace E. all of the above |
| Which of the following is a case of steady state heat transfer ___________________? |
| A. I.C. engine B. air preheaters C. heating of building in winter D. all of the above E. none of the above |
| Thermal conductivity of water in general with rise in temperature ____________________? |
| A. increases B. decreases C. remains constant D. may increase or decrease depending on temperature E. none of the above |
| Temperature of steam at around 540°C can be measured by ____________________? |
| A. thermometer B. radiatiouv pyrometer C. thermistor D. thermocouple E. thermopile |
| Metals are good conductors of heat because________________? |
| A. their atoms collide frequently B. their atoms-are relatively far apart C. they contain free electrons D. they have high density E. all of the above |
| Cork is a good insulator because it has___________________? |
| A. free electrons B. atoms colliding frequency C. low density D. porous body E. all of the above |
| Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of__________________? |
| A. 0.002 B. 0.02 C. 0.01 D. 0.1 E. 0.5 |
| Thermal conductivity of air with rise in temperature__________________? |
| A. increases B. decreases C. remains constant D. may increase or decrease depending on temperature E. none of the above |
| Total heat is the heat required to__________________? |
| A. change vapour into liquid B. change liquid into vapour C. increase the temperature of a liquid or vapour D. convert water into steam and superheat it E. convert saturated steam into dry steam |
| Thermal conductivity of water at 20°C is of the order of_____________________? |
| A. 0.1 B. 0.23 C. 0.42 D. 0.51 E. 0.64 |
| The time constant of a thermocouple is_______________? |
| A. the time taken to attain the final temperature to be measured B. the time taken to attain 50% of the value of initial temperature difference C. the time taken to attain 63.2% of the value of initial temperature difference D. determined by the time taken to reach 100°C from 0°C E. none of the above |
| In heat transfer, conductance equals conductivity (kcal/hr/sqm/°C/cm) divided by ________________? |
| A. hr (time) B. sqm (area) C. °C (temperature) D. cm (thickness) E. kcal (heat). |
| Which of the following is expected to have highest thermal conductivity_______________? |
| A. steam B. solid ice C. melting ice D. water E. boiling water |
| Thermal conductivity of a material may be defined as the________________? |
| A. quantity of heat flowing in one second through one cm cube of material when opposite faces ^re maintained at a temperature difference of 1°C B. quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1°C C. heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces D. all of the above E. none of the above |
| Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in _________________? |
| A. electric heater B. steam condenser C. melting of ice D. refrigerator condenser coils E. boiler |
| The ratio of heat flow Q1/Q2 from two walls of same thickness having their thermal conductivities as ATj – 2K2 will be ________________? |
| A. I B. 0.5 C. 2 D. 0.25 E. 4.0 |
| Thermal diffusivity of a substance is ____________________? |
| A. proportional of thermal conductivity B. inversely proportional to k C. proportional to (k) D. inversely proportional to k2 E. none of the above |
| According to Prevost theory of heat exchange ___________________? |
| A. it is impossible to transfer heat from low temperature source to t high temperature source B. heat transfer by radiation requires no medium C. all bodies above absolute zero emit radiation D. heat transfer in most of the cases takes place by combination of conduction, convection and radiation E. rate of heat transfer depends on thermal conductivity and temperature difference |
| Thermal conductivity of glass-wool varies from sample to sample because of variation in ________________ ? |
| A. composition B. density C. porosity D. structure E. all of the above |
| Which of the following has least value of conductivity_________________? |
| A. glass B. water C. plastic D. rubber E. air |
| Heat flows from one body to other when they have_________________? |
| A. different heat contents B. different specific heat C. different atomic structure D. different temperatures E. none of the above |
| The amount of heat flow through a body by conduction is_______________? |
| A. directly proportional to the surface area of the body B. directly proportional to the temperature difference on the two faces of the body C. dependent upon the material of the body D. inversely proportional to the thickness of the body E. all of the above |
| Which of the following has maximum value of thermal conductivity________________? |
| A. aluminium B. steel C. brass D. copper E. lead |
| Heat transfer by radiation mainly depends upon___________________? |
| A. its temperature B. nature of the body C. kind and extent of its surface D. all of the above E. none of the above |
| Moisture would find its way into insulation by vapour pressure unless it is prevented by __________________ ? |
| A. high thickness of insulation B. high vapour pressure C. less thermal conductivity insulator D. a vapour seal E. all of the above |
| Thermal diffusivity is ____________________? |
| A. a dimensionless parameter B. function of temperature C. used as mathematical model D. a physical property of the material E. useful in case of heat transfer by radiation |
| Thermal conductivity of wood depends on_______________? |
| A. moisture B. density C. temperature D. all of the above E. none of the above |
| Film coefficient is defined as Inside diameter of tube________________? |
| A. Equivalent thickness of film B. Thermal conductivity Equivalent thickness of film Specific heat x Viscocity C. Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity D. Film coefficient x Inside diameter Thermalconductivity E. none of the above |
| Unit of thermal diffusivity is_________________? |
| A. m2/hr B. m2/hr°C C. kcal/m2 hr D. kcal/m.hr°C E. kcal/m2 hr°C |
| In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by___________________? |
| A. convection B. radiation C. conduction D. both convection and conduction E. none of the above |
| The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as ________________? |
| A. emissivity B. transmissivity C. reflectivity D. intensity of radiation E. absorptivity |
| A grey body is one whose absorptivity_________________? |
| A. varies with temperature B. varies with wavelength of the incident ray C. is equal to its emissivity D. does not vary with temperature and. wavelength of the incident ray E. none of the above |
| Heat conducted througfi unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called__________________? |
| A. thermal resistance B. thermal coefficient C. temperature gradient D. thermal conductivity E. heat-transfer |
| Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of____________________? |
| A. 1 :1 B. 2: 1 C. 1 : 2 D. 4 : 1 E. 1 : 4 |
| Emissivity of a white polished body in comparison to a black body is________________? |
| A. higher B. lower C. same D. depends upon the shape of body E. none of the above |
| A non-dimensional number generally associated with natural convection heat transfer is________________? |
| A. Grashoff number B. Nusselt number C. Weber number D. Prandtl number E. Reynold number |
| In heat exchangers, degree of approach is defined as the difference between temperatures of________________? |
| A. cold water inlet and outlet B. hot medium inlet and outlet C. hot medium outlet and cold water inlet D. hot medium outlet and cold water outlet E. none of the above |
| A steam pipe is to be insulated by two insulating materials put over each other . For best results__________________? |
| A. better insulation should be put over pipe and better one over it B. inferior insulation should be put over pipe and better one over it C. both may be put in any order D. whether to put inferior OIL over pipe or the better one would depend on steam temperature E. unpredictable |
| According of Kirchhoff’s law______________________? |
| A. radiant heat is proportional to fourth power of absolute temperature B. emissive power depends on temperature C. emissive power and absorptivity are constant for all bodies D. ratio of emissive power to absorptive power is maximum for perfectly black body E. ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body |
| LMTD in case of counter flow heat exchanger as compared-to parallel flow heat exchanger is _________________? |
| A. higher B. lower C. same D. depends on the area of heat exchanger E. depends on temperature conditions |
| Fourier’s law of heat conduction is valid for_________________? |
| A. one dimensional cases only B. two dimensional cases only C. three dimensional cases only D. regular surfaces having non-uniform temperature gradients E. irregular surfaces |
| In counter flow heat exchangers_________________? |
| A. both the fluids at inlet (of heat ex¬changer where hot fluid enters) are in their coldest state B. both the fluids at inlet are in their hot¬test state C. both the fluids .at exit are in their hottest state D. one fluid is in hottest state and other in coldest state at inlet E. any combination is possible depending on design of heat exchanger |
| The concept of overall coefficient of heat transfer is used in case of heat transfer by________________? |
| A. conduction B. convection C. radiation D. conduction and convection E. convection and radiation |
| Joule sec is the unit of_________________? |
| A. universal gas constant B. kinematic viscosity C. thermal conductivity D. Planck’s constant E. none of the above |
| According to Kirchoff’s law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a _________________? |
| A. grey body B. brilliant white polished body C. red hot body D. black body E. none of the above |
| All radiations in a black body are___________________? |
| A. reflected B. refracted C. transmitted D. absorbed E. partly reflected and partly absorbed |
| The unit of overall coefficient of heat transfer is___________________? |
| A. kcal/m2 B. kcal/hr °C C. kcal/m2 hr °C D. kacl/m hr °C E. kcal/m3 hr °C |
| The value of the wavelength for maximum emissive power is given by ___________________? |
| A. Wien’s law B. Planck’s law C. Stefan’s law D. Fourier’s law E. Kirchhoff’s law |
| Total emissivity of polished silver compared to black body is___________________? |
| A. same B. higher C. more or less same D. very much lower E. very much higher |
| The value of Prandtl number for air is about _______________________? |
| A. 0.1 B. 0.3 C. 0.7 D. 1.7 E. 10.5 |
| The energy distribution of an ideal reflector at higher temperatures is largely in the range of ___________________? |
| A. shorter wavelength B. longer wavelength C. remains same at all wavelengths D. wavelength has nothing to do with it E. none of the above |
| Which of the following property of air does not increase with rise in temperature ________________? |
| A. thermal conductivity B. thermal diffusivity C. density D. dynamic viscosity E. kuiematic viscosity |
| In free con-vection heat transfer, Nusselt number is function of________________? |
| A. Grashoff no. and Reynold no B. Grashoff no and Prandtl no. C. Prandtl no. and Reynold no D. Grashoff no., Prandtl no and Reynold no E. none of the above |
| According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to___________________? |
| A. absolute temperature B. square of temperature C. fourth power of absolute temperature D. fourth power of temperature E. cube of absolute temperature |
| Log mean temperature difference in case of counter flow compared to parallel flow will be________________? |
| A. same B. more C. less D. depends on other factors E. none of the above |
| The unit of Stefan Boltzmann constant is ____________________? |
| A. watt/cm2 °K B. watt/cm4 °K C. watt2/cm °K4 D. watt/cm2 °K4 E. watt/cm2 °K2 |
| Stefan Boltzmann law is applicable for heat transfer by __________________? |
| A. conduction B. convection C. radiation D. conduction and radiation combined E. convection and radiation combined |
| Thermal diffusivity of a substance is __________________? |
| A. directly proportional to thermal con¬ductivity B. inversely proportional to density of substance C. inversely proportional to specific heat D. all of the above E. none of the above |
| The thermal diffusivities for gases are generally_____________________? |
| A. more than those for liquids B. less than those for liquids C. more than those for solids D. dependent on the viscosity E. same as for the liquids |
| A grey body is one whose absorptivity _________________? |
| A. varies with temperature B. varies with the wave length of incident ray C. varies with both D. does not vary with temperature and wave length of the incident ray E. there is no such criterion |
| Planck’s law holds good for________________? |
| A. black bodies B. polished bodies C. all coloured bodies D. all of the above E. none of the above |
| A perfect black body is one which_______________? |
| A. is black in colour B. reflects all heat C. transmits all heat radiations D. abslprbs heat radiations of all wave lengths falling on it E. fully opaque |
| If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of___________________? |
| A. 3 B. 6 C. 9 D. 27 E. 81 |
| In regenerator type heat exchanger, heat transfer takes place by___________________? |
| A. direct mixing of hot and cold fluids B. a complete separation between hot and cold fluids C. flow of hot and cold fluids alternately over a surface D. generation of heat again and again E. indirect transfer |
| Two plates spaced 150 mm apart are maintained at 1000°C and 70°C. The heat transfer will take place mainly by ___________________? |
| A. convection B. free convection C. forced convection D. radiation E. radiation and convection |
| Depending on the radiating properties, body will be transparent when________________? |
| A. p = 0, x = 0 and a = 1 B. p=l,x = 0,anda = 0 C. p = 0, T= l,anda = 0 D. X = 0, a + p = 1 E. a = 0,x + p= 1 |
| Absorptivity of a body will be equal to its emissivity___________________? |
| A. at all temperatures B. at one particular temperature C. when system is under thermal equi-librium D. at critical temperature E. for a polished body |
| The amount of radiation mainly depends on___________________? |
| A. nature of body B. temperature of body C. type of surface of body D. all of the above E. none of the above |
| The ratio of the energy absorbed by the body to total energy falling on it is called_________________? |
| A. absorptive power B. emissive power C. absorptivity D. emissivity E. none of the above |
| The emissive power of a body depends upon its___________________? |
| A. temperature B. wave length C. physical nature D. all of the above E. none of the above |
| 40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is____________________? |
| A. 0.45 B. 0.55 C. 0.40 D. 0.75 E. 0.60 |
| The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit_______________? |
| A. temperature B. thickness C. area D. time E. area and time |
| Depending on the radiating properties, a body will be black when_________________? |
| A. p = 0, x = 0 and a = 1 B. p= l,T = 0anda = 0 C. p = 0, x = 1 and a = 0 D. x = 0, a + p = 0 E. a = 0,x + p= 1. where a = absorptivity, p == reflectivity, X = transmissivity |
| According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to____________________? |
| A. absolute temperature B. T2 C. T5 D. t E. l/T |
| The thermal diffusivities for solids are generally__________________? |
| A. less than those for gases B. jess than those for liquids C. more than those for liquids and gases D. more or less same as for liquids and gases E. zerci |
| The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as_________________? |
| A. Krichoff’s law B. Stefan’s law C. Wien’ law D. Planck’s law E. Black body law |
| Depending on the radiating properties, a body will be white when_________________? |
| A. p = 0, x = 0 and a = 1 B. p=l,T = 0anda = 0 C. p = 0, x = 1 and a = 0 D. x = 0, a + p = 1 E. a = 0, x + p = 1. |
| where a = absorptivity, p = reflectivity, x = transmissivity |
| Depending on the radiating properties, a body will be opaque when _________________? |
| A. p = 0, x = 0 and a = 1 B. p=l,x = 0anda = 0 C. p = 0, x = 1 and a = 0 D. x – 0, a + p = 1 E. a=0,x + p= 1. |
| where a = absorptivity, p = reflectivity, X = transmissivity |
| According to Wien’s law, the wavelength corresponding to maximum energy is proportion to ________________? |
| A. absolute temperature (T) B. I2 C. f D. t E. 1/r |
| The unit of work or energy in S.I. units is_______________? |
| A. newton B. pascal C. kilogram meter D. watt E. joule |
| Forces are called concurrent when their lines of action meet in________________? |
| A. one point B. two points C. plane D. perpendicular planes E. different planes |
| Which is the correct statement about law of polygon of forces ? |
| A. if any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium B. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium C. if a polygon representing forces acting at a point is closed then forces are in equilibrium D. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium E. none of the above. |
| If a number of forces act simultaneously on a particle, it is possible _____________________? |
| A. not a replace them by a single force B. to replace them by a single force C. to replace them by a single force through C.G. D. to replace them by a couple E. to replace them by a couple and a force |
| A force is completely defined when we specify_______________? |
| A. magnitude B. direction C. point of application D. all of the above E. none of the above |
| Effect of a force on a body depends upon ________________? |
| A. magnitude B. direction C. position or line of action D. all of the above E. none of the above |
| A force acting on a body may_________________? |
| A. introduce internal stresses B. balance the other forces acting on it C. retard its motion D. change its motion E. all of the above |
| The unit of force in S.I. units is________________? |
| A. kilogram B. newton C. watt D. dyne E. joule |
| Forces are called coplanar when all of them acting on body lie in __________________? |
| A. one point B. one plane C. different planes D. perpendicular planes E. different points |
| Which of the following statement is wrong ? |
| A. The mortise gauge has two scribing pins B. The gouges are chisels with a hollow shaped blade C. An auger is a planning tool D. all of these |
| Pick up the wrong statement? |
| A. In a heterogeneous or solid-fuel reactor, the fuel is mixed in a regular pattern within moderator. B. Slow or thermal neutrons have energy of the order or 0.025 eV C. Fast neutrons have energies above 1000 eV D. Fast reactor uses moderator E. Most serious drawback in using water as coolant in nuclear plants is its high vapour pressure |
| Pick up the false statement ? |
| A. gas turbine is a self-starting unit B. gas turbine does not require huge quantity of water like steam plant C. exhaust losses in gas turbine are high due to large mass flow rate D. overall efficiency of gas turbine plant is lower than that of a reciprocating engine E. gas turbine can be easily started and stopped and thus is best suited for peaking demands |
| Pick up the correct statement? |
| A. closed cycle gas turbine is an I.C engine B. gas turbine uses same working fluid over and over again C. air-fuel ratio in a gas turbine is 100 : 1 D. ideal efficiency of closed cycle gas turbine plant is more than carnot cycle efficiency E. thrust in turbo-jet is produced by nozzle exit gases |
| Pick up the wrong statement ? |
| A. pulsojet requires no ambient air for propulsion B. ramjet-engine has no turbine C. turbine drives compressor in a burbojet D. bypass turbo-jet engine increases the thrust without adversely affecting, the propulsive efficiency and fuel economy E. propeller is an indirect reaction device |
| Pick up the correct statement ? |
| A. large gas turbines use radial inflow turbines B. gas turbines have their blades similar to steam turbine C. gas .turbine’s blade will appear as impulse section at the hub and as a reaction section at tip D. gas turbines use both air and liquid cooling E. all of the above are correct. |
| Choose the correct statement ________________? |
| A. gas turbine requires lot of cooling water B. gas turbine is capable of rapid start up and loading C. gas turbines have flat efficiency at part loads D. gas turbines have high standby losses and require lot of maintenance E. gas turbines can be used to generate power only |
| Pick up the wrong statement ? |
| A. large gas turbines employ axial flow compressors B. axial flow compressors are more stable than centrifugal type compressors but not as efficient C. axial flow compressors have high capacity and efficiency D. axial flow compressors have instability region of operation E. centrifugal compressors are used mainly on low flow pressure ratio gas turbines |
| Pick up the correct statement ? |
| A. gas turbine uses low air-fuel ratio to economise on fuel B. gas turhine uses high air-fuel ratio to reduce outgoing temperature C. gas turbine uses low air-fuel ratio to develop the high thrust required D. all of the above E. none of the above |
| Pick up the wrong statement ? |
| A. centrifugal compressors deliver prac-tically constant pressure over a considerable range of capacities B. Axial flow compressors have a sub-stantially constant delivery at variable pressures C. centrifugal compressors have a wider stable operating range than axial flow compressors D. axial flow compressors are bigger in diameter compared to centrifugal type E. axial flow compressors apt to be longer as compared to centrifugal type |
| Which of the following is secondary fuel ? |
| A. Th232andU238 B. U233andPu239 C. U233andPu238 D. non oh these |
| Dynamic friction as compared to static friction is___________________? |
| A. same B. more C. less D. may be less of more depending on nature of surfaces and velocity E. has no correlation |
| Limiting force of friction is the__________________? |
| A. tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction B. ratio of limiting friction and normal reaction C. the friction force acting when the body is just about to move D. the friction force acting when the body is in motion E. minimum force of friction |
| Tangent of angle of friction is equal to__________________? |
| A. kinetic friction B. limiting friction C. angle of repose D. coefficient of friction E. friction force |
| A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is \i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will____________________? |
| A. remain horizontal B. slant up towards direction of pull C. slant down towards direction of pull D. unpredictable E. none of the above |
| The algebraic sum of moments of the forces forming couple about any point in their plane is_________________? |
| A. equal to the moment of the couple B. constant C. both of above are correct D. both of above are wrong E. none of the above |
| The necessary condition for forces to be in equilibrium is that these should be_________________? |
| A. coplanar B. meet at one point ; C. both A. and B. above D. all be equal E. something else |
| A cable with a uniformly distributed load per horizontal meter run will take the following shape________________? |
| A. straight line B. parabola C. hyperbola D. elliptical E. part of a circle |
| In actual machines_______________? |
| A. mechanical advantage is greater than velocity ratio B. mechanical advantage is equal to velocity ratio C. mechanical advantage is less than velocity ratio D. mechanical advantage is unity E. none of the above |
| In ideal machines__________________? |
| A. mechanical advantage is greater than velocity ratio B. mechanical advantage is equal to velocity ratio C. mechanical advantage is less than velocity ratio D. mechanical advantage is unity E. none of the above |
| The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of_______________? |
| A. friction B. limiting friction C. repose D. kinematic friction E. static friction |
| The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is__________________? |
| A. same B. double C. half D. four times E. one fourth |
| The C.G. of a plane lamina will not be at its geometrical centre in the case of a__________________? |
| A. right angled triangle B. equilateral triangle C. square D. circle E. rectangle |
| The C.G. of a right circular solid cone of height h lies at the following distance from the base______________? |
| A. h/2 B. J/3 C. h/6 D. h/4 E. 3/i/5 |
| A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal_________________? |
| A. density of metal can’t be determined B. metal is twice as dense as water C. metal will float in water D. metal is twice as dense as unknown fluid E. none of the above |
| Which of the following is not the unit of energy_________________? |
| A. kg m B. kcal C. wattr D. watt hours E. kg m x (m/sec)2 |
| The C.G. of a solid hemisphere lies on the central radius 3r________________? |
| A. at distance — from the plane base 3r B. at distance — from the plane base 3r C. at distance — from the plane base 3r D. at distance — from the plane base or E. at distance — from the plane base |
| Which of the following is the locus of a point that moves in such a manner that its distance from a fixed point is equal to its distance from a fixed line multiplied by a constant greater than one___________________? |
| A. ellipse B. hyperbola C. parabola D. circle E. none of the above |
| A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly_________________? |
| A. 38 m B. 62.5 m C. 96 m D. 124 m E. 240 m |
| A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to___________________? |
| A. 25 B. 50 C. 100 D. 250 E. 500 |
| If n = number of members andy = number of joints, then for a perfect frame, n =_________________? |
| A. j-2 B. 2j-l C. 2/-3 D. 3/-2 E. 2/ -4 |
| The co-efficient of friction depends upon_______________? |
| A. nature of surfaces B. area of contact C. shape of the surfaces D. ail of the above. E. A. and B. above |
| A single force and a couple acting in the same plane upon a rigid body_____________________? |
| A. balance each other B. cannot balance each other C. produce moment of a couple D. are equivalent E. none of the above |
| The maximum frictional force which comes into play when a body just begins to slide over another surface is called__________________? |
| A. limiting friction B. sliding friction C. rolling friction D. kinematic friction E. dynamic friction |
| The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to _________________? |
| A. Wtan(a + ) B. Wtan(a-) C. Wcos(a + ) D. Wsin(a + ) E. W (sin a + cos ). |
| Coulomb friction is the friction between _________________? |
| A. bodies having relative motion B. two dry surfaces C. two lubricated surfaces D. solids and liquids E. electrically charged particles |
| A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is_______________? |
| A. 0° B. 30° C. 45° D. 60° E. 90°. |
| A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t – 4), the acceleration of the particle will be given by the equation __________________? |
| A. 3t2-lt B. 3t2+2t C. 6f-8 D. 6f-4 E. 6t2-8t |
| If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella___________________? |
| A. more inclined when moving B. less inclined when moving C. more inclined when standing D. less inclined when standing E. none of the above |
| A body of weight W on inclined plane of a being pulled up by a horizontal force P will be on the point of motion up the plane when P is equal to________________? |
| A. W B. W sin (a + $) C. Wtan(a + <|)) D. W\an(a-) E. Wtana |
| Coefficient of friction is the_________________? |
| A. angle between a normal reaction and the resultant of normal reaction and the limiting friction B. ratio of limiting friction and normal reaction C. the friction force acting when the body is just about to move D. the friction force acting when the body is in motion E. tangent of angle of repose |
