Heat Transfer MCQs

Question 1

Pick out the correct statement.

Accepted Answer

In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity

Answer

1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F

Answer

In unsteady state heat conduction, heat flows in the direction of temperature rise

Answer

In heat transfer by forced convection, Grashoff number is very important

Question 2

Value of Prandtl number for water ranges from

Accepted Answer

5 to 10

Answer

1 to 2

Answer

100 to 500

Answer

1000 to 2000

Question 3

1 BTU/hr.ft.°F is equal to __________ kcal/hr. m.°C.

Accepted Answer

1.49

Answer

1

Answer

4.88

Answer

None of these

Question 4

A process stream of dilute aqueous solution flowing at the rate of 10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1. A 1 - 1 shell and tube heat exchanger is available. The best arrangement is

Accepted Answer

Counter flow with process stream on shell side

Answer

Counter flow with process stream on tube side

Answer

Parallel flow with process stream on shell side

Answer

Parallel flow with process stream on tube side

Question 5

Low thermal conductivity of heat insulating materials is due to its

Accepted Answer

High proportion of air space

Answer

Dense structure

Answer

High specific heat

Answer

None of these

Question 6

The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by

Accepted Answer

Transient conduction

Answer

Forced convection

Answer

Natural convection

Answer

Steady state conduction

Question 7

Boiling point elevation of a solution of NaOH

Accepted Answer

Both B and C

Answer

Increases rapidly with temperature rise

Answer

Is almost independent of temperature

Answer

Is almost independent of pressure

Question 8

In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always

Accepted Answer

< 1

Answer

> 1

Answer

1

Answer

∞

Question 9

In counter flow compared to parallel flow,

Accepted Answer

Both A and B

Answer

LMTD is greater

Answer

Less surface area is required for a given heat transfer rate

Answer

More surface area is required for a given heat transfer rate