Chemical Engineering - Chemical Engineering Basics

36. 

Which of the following represents the correct time-temperature curve when a block of metal is heated above room temperature & then left to cool in the room following Newton's law of cooling in which the rate of temperature drop will go on decreasing with the passage of time.

A.
B.
C.
D.

Answer: Option C

Explanation:

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37. 

Pick out the wrong statement about coating/electroplating of metals.

A. Phosphate coating is used as an excellent base for paints & enamels.
B. Phosphate coating is less corrosion resistant than chromate coating.
C. The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode.
D. Calorising is the process of coating steel with chromium.

Answer: Option D

Explanation:

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38. 

In case of a, centrifugal pump, the ratio h1/h2 is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller).

A. mechanical
B. overall
C. volumetric
D. impeller

Answer: Option A

Explanation:

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39. 

Brinell hardness number (BHN) of a material is a number, which has

A. no dimension.
B. unit of length.
C. unity of force/area.
D. unit of force/length.

Answer: Option C

Explanation:

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40. 

Vanadium addition to steel improves its

A. high temperature oxidation resistance.
B. fatigue strength.
C. heat treatability by quenching.
D. hardenability.

Answer: Option D

Explanation:

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