Chemical Engineering - Chemical Engineering Basics

41. 

In 18-4-1 high speed steel, 18, 4 & 1 respectively denote the percentage of

A. chromium, tungsten & vanadium.
B. tungsten, chromium & vanadium.
C. tungsten, vanadium & chromium.
D. tungsten, chromium & molybdenum.

Answer: Option B

Explanation:

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42. 

Role of a "collector" in froth floatation is to

A. form a water repelling film on the mineral surface.
B. create and stabilise the froth.
C. act as a surface.
D. collect the minerals according to their specific gravity.

Answer: Option A

Explanation:

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43. 

For the running of power generating turbines, the steam used should be

A. wet
B. superheated
C. at ordinary pressure
D. none of these

Answer: Option B

Explanation:

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44. 

Creep consideration is the most important in case of the

A. blades of gas turbines.
B. steam engine flywheel.
C. cast iron pipes.
D. cycle chains.

Answer: Option A

Explanation:

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45. 

The diffusion co-efficient of Ni in Cu at 1000 K is 1.93 x 10-16 m2 . S-1 and it is 1.94 x 10-14 m2 S-1 at 1200 K. The activation energy (in k. J.mole-1 ) for the diffusion of Ni in Cu is

A. 130
B. 180
C. 230
D. 250

Answer: Option C

Explanation:

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