August 2022

Question: Electrolytic reduction cell used for conversion of calcined Al2O3 to Al is a carbon lined furnace operating at 800-900 °C. The purpose of electric current supplied to the furnace is to
[A].

achieve very high purity of aluminium (99.9%).

[B].

keep the electrolyte in liquid condition by the generation of heat.

[C].

electrolytically dissociate alumina.

[D].

both(b) & (c).

Answer: Option D

Explanation:

No answer description available for this question.

Question: Electrometallurgical methods of metal extraction is normally used for those metals
[A].

whose oxide/ore is not reduced by carbon.

[B].

which fall in the category of alkali & alkaline earth metals.

[C].

which stands higher in the electrochemical series of the metal.

[D].

all (a), (b) & (c).

Answer: Option D

Explanation:

No answer description available for this question.

Question: Galvanic corrosion
[A].

occurs in a bimetal couple.

[B].

occurs in highly stressed metallic parts only.

[C].

is exemplified by caustic embrittlement of boiler tubes.

[D].

is also called dezincification.

Answer: Option A

Explanation:

No answer description available for this question.

Question: Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of __________ gms of zinc per m2 of steel strip.
[A].

5-10

[B].

1000-1500

[C].

120-500

[D].

1500-3000

Answer: Option C

Explanation:

No answer description available for this question.

Question: Factor of safety is the ratio of the __________ stress to the working stress.
[A].

tensile

[B].

compressive

[C].

yield

[D].

bearing

Answer: Option C

Explanation:

No answer description available for this question.

Question: Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.
[A].

atoms

[B].

neutrons

[C].

nucleons

[D].

electrons

Answer: Option A

Explanation:

No answer description available for this question.

Question: An ideal material for making cooking vessels should have
[A].

high heat capacity.

[B].

low heat capacity.

[C].

high thermal conductivity.

[D].

both (b) and (c).

Answer: Option D

Explanation:

No answer description available for this question.

Question: Heat required to raise the temperature of a body by 1 °C is called its
[A].

heat capacity.

[B].

specific heat capacity.

[C].

thermal conductivity.

[D].

water equivalent.

Answer: Option A

Explanation:

No answer description available for this question.

Question: A solid aluminium ball, when quenched in a water bath maintained at 40°C, cools down from 550°C to 450°C in 20 seconds. The expected temperature of the ball after next 20 seconds may be about __________ °C.
[A].

370

[B].

340

[C].

320

[D].

300

Answer: Option A

Explanation:

No answer description available for this question.

Question: Paint spray gun works on the principle of
[A].

Bernoulli’s theorem.

[B].

Boyle’s law.

[C].

Newton’s law of viscosity.

[D].

none of these.

Answer: Option A

Explanation:

No answer description available for this question.