MECHANICAL ENGINEERING MCQ SECTION 31

 301. Which sample of concrete can be expected to have the highest value of thermal

conductivity?

(A) Dry concrete

(B) Dry concrete with 0.4 % reinforcement

(C) Concrete having 10 % moisture (by volume)

(D) Concrete having 10% moisture by volume and 0.6% reinforcement

Answer: -Dry concrete with 0.4 % reinforcement

302. A dimension heat transfer coefficient which gives a measure of the ratio of the

heat transfer rate to the rate at which heat would be conducted within the fluid

under temperature gradient is known as

(A) Reynold’s number

(B) Grashoff’s number

(C) Nusselt number

(D) Stanton number

Answer: -Nusselt number

303. Formation of frost on evaporator in refrigerator

(A) Results in loss of heat due to poor heat transfer

(B) Increases heat transfer rate

(C) Is immaterial

(D) Can be avoided by proper design

Answer: -Results in loss of heat due to poor heat transfer

304. Presence of moisture in Feron refrigeration system causes

(A) Ineffective refrigeration

(B) Damage to compressor

(C) Freezing at automatic regulating valve

(D) None of the above

Answer: -Freezing at automatic regulating valve

305. The phenomenon of emf developed between two dissimilar metals in contact

is known as

(A) Seeback effect

(B) Thomson effect

(C) Peltier effect

(D) Thermocouple effect

Answer: -Seeback effect

306. A stremline and an equipotential line in a flow field

(A) Are parallel to each other

(B) Are perpendicular to each other

(C) Intersect at an acute angle

(D) Are identical

Answer: -Are perpendicular to each other

307. The coefficient of restitution of a perfectly plastic impact is

(A) 0

(B) 1

(C) 2

(D) V

Answer: -0

308. In a rolling process, the state of stress of the material undergoing deforming is

(A) Pure compression 

(B) Pure shear

(C) Compression and shear 

(D) Tension and shear

Answer: -Compression and shear

309. For a ductile material, toughness is a measure of

(A) Resistance to scratching

(B) Ability to absorb energy up to fracture

(C) Ability to absorb energy till elastic limit

(D) Resistance to indentation

Answer: -Ability to absorb energy up to fracture

310. In order to have maximum power from a Pelton turbine, the bucket speed

must be

(A) Equal to the jet speed

(B) Equal to half the jet speed

(C) Equal to twice the jet speed

(D) Independent of the jet speed

Answer: -Equal to half the jet speed