mechanical engineering MCQs – Page 7

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

mechanical engineering Mcqs

1. compressors gas turbines and jet engines 2. theory of machines 3. nuclear power plants 4. engineering materials 5. strength of materials mechanical engineering 6. thermodynamics 7. heat transfer 8. i c engines 9. steam boilers engines nozzles and turbines 10. engineering mechanics 11. fluid mechanics mechanical engineering 12. production technology 13. machine design 14. hydraulic machines 15. workshop technology 16. refrigeration and air conditioning

121. Which of the following are ferrite materials__________________?
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A. U238andTh239

B. none of the above

C. U233andPu239

D. U238andPu239

E. U

122. Maximum temprature in a gas turbine is of the order of COMPRESSORS, GAS TURBINES AND JET ENGINES______________________?
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A. 1000C

B. 1500C

C. 2000C

D. 2500C

E. 700C

123. In reaction turbine, draft tube is used_____________________?
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A. to transport water downstream without eddies

B. to increase flow rate

C. to convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section

D. for safety of turbine

E. none of the above

124. The fuel consumption in gas turbines is accounted for by___________________?
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A. low.er heating value

B. highest calorific value

C. higher calorific value

D. heating value

E. higher heating value

125. According to fan laws, at constant pressure, the speed capacity and power vary_________________?
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A. directly as the air or gas density

B. inversely as square root of density

C. as square root of density

D. as square of density

E. inversely as density

126. Diffuser in a compressor is used to _____________________?
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A. convert pressure energy into kinetic energy

B. convert kinetic energy into pressure energy

C. increase degree of reaction

D. increase velocity

E. make the flow stream-line

127. As the value of index is decreased, the volumetric efficiency will___________________?
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A. increase

B. remain unaffected

C. decrease

D. may increase/decrease depending on compressor clearance

E. none of the above

128. Rotary compressors are suitable for ____________________?
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A. large discharge at high pressure

B. low discharge at low pressure

C. large discharge at low pressure

D. low discharge at high pressure

E. there is no such limitation

129. Specific speed for reaction turbines ranges from___________________?
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A. 0 to 4.5

B. 80 to 200

C. 10 to 100

D. none of the above

E. 250 to 300

130. Turbo propeller has the following additional feature over the turbojet __________________?
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A. diffuser

B. peopeller

C. intercooler

D. starting engine

E. turbine and combustion chamber

131. Any change in load is adjusted by adjusting following parameter on turbine______________?
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A. blade velocity

B. absolute velocity

C. flow

D. net head

E. relative velocity of flow at inlet

132. A hydraulic accumulator normally consists of________________?
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A. two co-axial rams and two cylinders

B. special type of pump with storage device and a pressure regulator

C. a cylinder and a ram

D. two cylinders, two rams and a storage device

E. a cylinder, a piston, storage tank and control valve

133. Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of____________________?
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A. lower discharge

B. lower speed of operation

C. all of the above

D. high initial and maintenance cost

E. necessity of air vessel

134. The main purpose of reheating in gas turbine is to__________________?
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A. reduce turbine size

B. increase speed

C. increase pressure ratio

D. increase power output

E. increase temperature

135. A gas turbine used in air craft should have______________________?
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A. high h.p. and low weight

B. high speed and high h.p.

C. small frontal area and high h.p.

D. all of the above

E. low weight and small frontal area

136. Actual compression curve is___________________?
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A. same as isothermal

B. none of the above

C. better than isothermal and adiabatic

D. in between isothermal and adiabatic

E. same as adiabatic

137. When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be__________________?
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A. nearly horizontal

B. first rise and then fall

C. horizontal

D. steep

E. none of the above

138. In a centrifugal pump casing, the flow of water leaving the impeller, is___________________?
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A. free vortex motion

B. none of the above

C. radial flow

D. forced vortex

E. rectilinear flow

139. Reheating in gas turbine results in___________________?
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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

140. Propulsion efficiency of the following order-is obtained in practice _______________?
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A. 60%

B. 50%

C. 85%.

D. 34%

E. 72%

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