Mechanical Engineering Archives

5121. The total radiation from a black body per second per unit area is __________ fourth power of the absolute temperature. This statement is known as Stefan-Boltzmann law.

[A]. equal to

[B]. directly proportional to

[C]. inversely proportional to

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✅ The correct answer is option B.

5122. The air gap between the central electrode and ground (or side) electrode of a spark plug is around

[A]. 0.2 mm

[B]. 0.5 mm

[C]. 1 mm

[D]. 1.5 mm

✅ The correct answer is option C.

5123. The low pressure acetylene is produced at the welding site by the chemical reaction between water and calcium carbonate.

[A]. Correct

[B]. Incorrect

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✅ The correct answer is option B.

5124. The speed of a turbine runner is

[A]. directly proportional to H1/2

[B]. inversely proportional to H1/2

[C]. directly proportional to H3/2

[D]. inversely proportional to H3/2

✅ The correct answer is option A.

5125. The self ignition temperature of petrol is __________ as compared to diesel oil.

[A]. same

[B]. lower

[C]. higher

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✅ The correct answer is option C.

5126. The alloying element which increases residual magnetism and coercive magnetic force in steel for magnets is

[A]. chromium

[B]. nickel

[C]. vanadium

[D]. cobalt

✅ The correct answer is option D.

5127. Which of the following is correct?

[A]. Absolute pressure = Gauge pressure + Atmospheric pressure

[B]. Gauge pressure = Absolute pressure + Atmospheric pressure

[C]. Atmospheric pressure = Absolute pressure + Gauge pressure

[D]. Absolute pressure = Gauge pressure – Atmospheric pressure

✅ The correct answer is option A.

5128. The mechanical advantage of a lifting machine is the ratio of

[A]. distance moved by effort to the distance moved by load

[B]. load lifted to the effort applied

[C]. output to the input

[D]. all of the above

✅ The correct answer is option B.

5129. The cetane rating of Diesel fuel is in the order of

[A]. 25

[B]. 45

[C]. 70

[D]. 90

✅ The correct answer is option B.

5130. According to Indian standard specifications, 100 H6/g5 means that the

[A]. actual size is 100 mm

[B]. basic size is 100 mm

[C]. difference between the actual size and basic size is 100 mm

[D]. none of the above

✅ The correct answer is option B.