mechanical engineering MCQs – Page 25

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 Review each marked answer and report any item that may be outdated or unclear.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

481. A steam pipe is to be insulated by two insulating materials put over each other . For best results__________________?
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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

482. If a number of forces act simultaneously on a particle, it is possible _____________________?
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A. to replace them by a single force through C.G.

B. not a replace them by a single force

C. to replace them by a couple and a force

D. to replace them by a single force

E. to replace them by a couple

483. The presence of reflector in nuclear power plants results in___________________?
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A. controlled production of neutrons

B. complete absorption of neutrons

C. decreased leakage of neutrons

D. decrease of speed of neutrons

E. increased production of neutrons

484. 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____________________?
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A. 1 : 2

B. 4:01

C. 1:04

D. 1:01

E. 2:01

485. The center of gravity of a uniform lamina lies at____________________?
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A. the bottom surface

B. the mid point of its axis

C. all of the above

D. the center of heavy portion

E. none of the above

486. Cork is a good insulator because it has___________________?
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A. all of the above

B. atoms colliding frequency

C. free electrons

D. porous body

E. low density

487. A perfect black body is one which_______________?
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A. abslprbs heat radiations of all wave lengths falling on it

B. fully opaque

C. is black in colour

D. reflects all heat

E. transmits all heat radiations

488. The unit of Stefan Boltzmann constant is ____________________?
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A. watt/cm4 K

B. watt/cm2 K4

C. watt2/cm K4

D. watt/cm2 K

E. watt/cm2 K2

489. The following present serious difficulty in designing reactor shield_________________?
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A. none of the above

B. fast neutrons and gamma rays

C. alpha particles

D. thermal neutrons

E. beta particles

490. Frictional force encountered after commencement of motion is called ___________________?
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A. post friction

B. frictional resistance

C. limiting friction

D. dynamic friction

E. kinematic friction

491. A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to___________________?
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A. 25

B. 100

C. 250

D. 50

E. 500

492. Heat flowing from one side to other depends directly on ___________________?
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A. k up the wrong case?

493. In actual machines_______________?
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A. none of the above

B. mechanical advantage is less than velocity ratio

C. mechanical advantage is greater than velocity ratio

D. mechanical advantage is equal to velocity ratio

E. mechanical advantage is unity

494. Center of gravity of a solid cone lies on the axis at the height _____________________?
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A. none of the above

B. three-eighth of the total height above the base

C. one-third of the total height above base

D. one-half of the total height above base

E. one-fourth of the total height above base

495. Metals are good conductors of heat because________________?
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A. all of the above

B. their atoms collide frequently

C. they have high density

D. their atoms-are relatively far apart

E. they contain free electrons

496. Film coefficient is defined as Inside diameter of tube________________?
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A. none of the above

B. Equivalent thickness of film

C. Film coefficient x Inside diameter Thermalconductivity

D. Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity

E. Thermal conductivity Equivalent thickness of film Specific heat x Viscocity

497. Total emissivity of polished silver compared to black body is___________________?
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A. very much lower

B. higher

C. very much higher

D. same

E. more or less same

498. Thermal conductivity of glass-wool varies from sample to sample because of variation in ________________ ?
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A. composition

B. porosity

C. all of the above

D. structure

E. density

499. Which of the following is a vector quantity___________________?
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A. speed

B. energy

C. momentum

D. mass

E. angle

500. 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_________________?
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A. Stefans law

B. Black body law

C. Krichoffs law

D. Wien law

E. Plancks law

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