Heat Transfer MCQ Questions & Answers

21

Pick out the wrong statement.

A) The value of hydrostatic head increases with increase in vacuum in the effect in a multiple effect evaporator system B) Entering velocity of the liquid in the tubes of natural circulation evaporators is in the range of 0.3 to 0.9 metre/second C) Duhring's plot is used for calculating the concentration of solution D) In a multiple effect evaporation system, the number of effects is limited by the total boiling point rise

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Answer & Solution

Answer: Option C

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22

Thermal diffusivity of a material

A) Has the unit m²/sec B) Is defined as $$\frac{{\text{K}}}{{\rho .{{\text{C}}_{\text{p}}}}}$$ C) Is the ratio of thermal conductivity to thermal capacity D) All of the above

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Answer & Solution

Answer: Option D

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23

$$\frac{{{{\text{C}}_{\text{p}}}.\mu }}{{\text{K}}}$$ is termed as the __________ number.

A) Grashoff B) Nusselt C) Prandtl D) Stanton

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Answer & Solution

Answer: Option C

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24

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the

A) Surrounding temperature B) Average temperature of the fin C) Temperature of the fin end D) Constant temperature equal to that of the base

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Answer & Solution

Answer: Option D

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25

Double pipe heat exchangers are preferably useful, when

A) High viscosity liquid is to be cooled B) Requirement of heat transfer area is low C) Overall heat transfer co-efficient is very high D) A corrosive liquid is to be heated

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Answer & Solution

Answer: Option B

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26

The thermal boundary layer at N_Pr > 1

A) Is thicker than hydrodynamic boundary layer B) Is thinner than hydrodynamic boundary layer C) And the hydrodynamic boundary layer are identical D) Disappears

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Answer & Solution

Answer: Option B

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27

Maximum heat transfer rate is achieved in __________ flow.

A) Co-current B) Counter-current C) Turbulent D) Laminar

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Answer & Solution

Answer: Option C

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28

(N_Re.N_Pr)(D/L) is called the __________ number

A) Peclet B) Stanton C) Graetz D) None of these

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Answer & Solution

Answer: Option C

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29

In a boiling curve, the peak heat flux is called the __________ point.

A) Nusselt B) Leidenfrost C) Boiling D) Burnout

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Answer & Solution

Answer: Option D

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30

Sensible heat of hot industrial flue gases can not be recovered by a/an

A) Economiser B) Regenerator C) Ceramic recuperator D) None of these

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Answer & Solution

Answer: Option D

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Heat Transfer MCQ Questions & Answers | Chemical Engineering