Chemical Engineering - Chemical Engineering Basics

11. 

The best criterion for analysing an economic investment is the

A. rate of return criterion.
B. present value method.
C. salvage value.
D. future value method.

Answer: Option A

Explanation:

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12. 

Deformation band is absent in materials having __________ lattice crystal structure.

A. fcc
B. bcc
C. hcp
D. none of these

Answer: Option C

Explanation:

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13. 

Out of the following, the rays having the lowest wavelength is the

A. radio waves
B. ultrasonic waves
C. infra red rays
D. X-rays

Answer: Option A

Explanation:

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14. 

A fine grained grinding wheel should not be used for grinding __________ materials.

A. hard
B. brittle
C. soft & ductile
D. none of these

Answer: Option C

Explanation:

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15. 

What is the effect on the performance of the economiser in the thermal power plant boiler, if the feed water temperature is very low due to preheaters being out for repairs or starving of steam supply ?

A. It results in corrosion due to the condensation on the flue gas side of the economiser tubes due to handling of low temperature water.
B. Economiser tube life increases due to handling of low temperature water.
C. Heat transfer efficiency of economiser increases due to picking up high heat from the flue gases.
D. Scale formation rate on economiser tubes increases.

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.