Heat Transfer MCQ Questions & Answers

21

Crystal size in a continuous crystalliser depends upon the

A) Rate of heat transfer B) Degree of turbulence C) Degree of supersaturation D) All of the above

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Answer & Solution

Answer: Option D

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22

For heat flow through very thick walled cylinder, use____mean radius.

A) Arithmetic B) Logarithmic C) Geometric D) Either A or C

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Answer & Solution

Answer: Option B

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23

In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell)

A) 0.25 D B) 0.75 D C) 0.50 D D) None of these

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Answer & Solution

Answer: Option B

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24

Tube pitch is the __________ of tube diameters and the clearances.

A) Sum B) Difference C) Ratio D) None of these

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Answer & Solution

Answer: Option A

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25

The average heat transfer co-efficient for laminar film condensation on vertical surface is inversely proportional to (where, $$\Delta {\text{T}}$$ = Temperature drop across condensate film)

A) $${\left( {\Delta {\text{T}}} \right)^2}$$ B) $$\sqrt {\Delta {\text{T}}} $$ C) $${\left( {\Delta {\text{T}}} \right)^{\frac{1}{4}}}$$ D) $${\left( {\Delta {\text{T}}} \right)^{\frac{3}{2}}}$$

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Answer & Solution

Answer: Option C

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26

Multiple effect evaporators ar used to

A) Increase the steam economy & decrease the capacity B) Increase the steam economy & the capacity C) Decrease the steam economy & the capacity D) Decrease the steam economy & increase the capacity

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Answer & Solution

Answer: Option B

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27

Pick out the wrong statement.

A) The condensing film co-efficient is about 3 times lower for vertical condenser as compared to the equivalent horizontal condenser for identical situation B) Film co-efficient for vaporisation decreases as a result of vapor binding C) In industrial practice, sub-cooling of condensate is required, when the condensate is a volatile liquid and is to be transferred for storage D) Overall heat transfer co-efficient in a heat exchanger is controlled by the value of the film co-efficient, which is higher

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Answer & Solution

Answer: Option D

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28

Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because

A) Convection becomes important B) Conduction becomes important C) Radiation becomes important D) Sub-cooled boiling occurs

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Answer & Solution

Answer: Option C

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29

For a laminar flow of fluid in a circular tube, 'h₁' is the convective heat transfer co-efficient at velocity 'V₁'. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is

A) 1.26 h₁ B) 0.794 h₁ C) 0.574 h₁ D) 1.741 h₁

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Answer & Solution

Answer: Option B

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30

If h₁ = inner film co-efficient and /h₂ = outer film co-efficient, then the overall heat transfer co-efficient is

A) Always less than h₁ B) Always between h₁ and h₂ C) Always higher than h₂ D) Dependent on metal resistance

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Answer & Solution

Answer: Option B

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Heat Transfer MCQ Questions & Answers | Chemical Engineering