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Mechanical Engineering MCQs with Explanations

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531Mechanical EngineeringMedium

Stress relaxation is- the phenomenon ________?

Ain which deformation tends to loosen the joint and produces a stress reduced

Bin which stress remains constant on in-creasing load

Cstress reduces on increasing load

Din which parts are not loaded

Enone of the above

Correct answer

A. in which deformation tends to loosen the joint and produces a stress reduced

Explanation

The correct answer is in which deformation tends to loosen the joint and produces a stress reduced.

532Mechanical EngineeringMedium

Mach number is significant in________?

Aall of fhe above

Bfull immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.

Csimultaneous motion through two fluids where there is a surface of dis-continuity, gravity force, and wave making effects, as with ship’s hulls

Dnone of the above

Esupersonics, as with projectiles and jet propulsion

Correct answer

E. supersonics, as with projectiles and jet propulsion

Explanation

The correct answer is supersonics, as with projectiles and jet propulsion.

533Mechanical EngineeringMedium

Other method of reducing shock load in the above case can be________?

Ato decrease length

Bto increase length

Cnone of the above

Dother factors would decide same

Eunaffected by length

Correct answer

B. to increase length

Explanation

The correct answer is to increase length.

534Mechanical EngineeringMedium

A thin mild steel wire is loaded by adding loads in equal increments till it breaks. The extensions noted with increasing loads will behave as under________?

Aincrease uniformly first and then increase rapidly

Buniform throughout

Cfirst increase and then decrease

Dincrease uniformly

Eincrease rapidly first and then uniformly

Correct answer

A. increase uniformly first and then increase rapidly

Explanation

The correct answer is increase uniformly first and then increase rapidly.

535Mechanical EngineeringMedium

The flow in which the particles of a fluid attain such velocities that vary from point to point in magnitude and direction as well as from instant to instant, is known as________?

Asteady flow

Bone dimensional flow

Cuniform flow

Dstreamline flow

Eturbulent flow

Correct answer

E. turbulent flow

Explanation

The correct answer is turbulent flow.

536Mechanical EngineeringMedium

In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of________?

Aatmospheric air

Boxygen alone

Ccompressed air

Dvacuum

Eliquid hydrogen

Correct answer

C. compressed air

Explanation

The correct answer is compressed air.

537Mechanical EngineeringMedium

Hot wire anemometer is used to measure________?

Avelocity of gas

Bpressure intensity of liquid

Cdischarge

Dpressure intensity of gas

Correct answer

A. velocity of gas

Explanation

The correct answer is velocity of gas.

538Mechanical EngineeringMedium

Governor is used in automobile to________?

Adecrease the variation of speed

Bnone of the above

Cto control

Dto control SN

Eall of the above

Correct answer

D. to control SN

Explanation

The correct answer is to control SN.

539Mechanical EngineeringMedium

Which of the following is the case of heat transfer by radiation ________?

Aall of the above

Bcooling of parts in furnace

Cblast furnace

Dheat received by a person from fireplace

Eheating of building

Correct answer

D. heat received by a person from fireplace

Explanation

The correct answer is heat received by a person from fireplace.

540Mechanical EngineeringMedium

Maximum percentage of carbon in ferrite is________?

A0.1%

B0.025%

C0.8%.

D0.06%

E0.25%

Correct answer

B. 0.025%

Explanation

The correct answer is 0.025%.

Stress relaxation is- the phenomenon ________?

Ain which deformation tends to loosen the joint and produces a stress reduced

Bin which stress remains constant on in-creasing load

Cstress reduces on increasing load

Din which parts are not loaded

Enone of the above

Correct answer

A. in which deformation tends to loosen the joint and produces a stress reduced

Explanation

The correct answer is in which deformation tends to loosen the joint and produces a stress reduced.

Mach number is significant in________?

Aall of fhe above

Bfull immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.

Csimultaneous motion through two fluids where there is a surface of dis-continuity, gravity force, and wave making effects, as with ship’s hulls

Dnone of the above

Esupersonics, as with projectiles and jet propulsion

Correct answer

E. supersonics, as with projectiles and jet propulsion

Explanation

The correct answer is supersonics, as with projectiles and jet propulsion.

A thin mild steel wire is loaded by adding loads in equal increments till it breaks. The extensions noted with increasing loads will behave as under________?

Aincrease uniformly first and then increase rapidly

Buniform throughout

Cfirst increase and then decrease

Dincrease uniformly

Eincrease rapidly first and then uniformly

Correct answer

A. increase uniformly first and then increase rapidly

Explanation

The correct answer is increase uniformly first and then increase rapidly.