GATE CH Heat Transfer PYQs & Answers — Page 2

Questions 11–20 of 57. Imported answers require independent review unless marked reviewed.

The opposite faces of a metal slab of thickness 5 cm and thermal conductivity 400 W m

°C

are maintained at 50 °C and 200 °C. The area of each face is 0.02 m

. Assume that the heat transfer is steady and occurs only in the direction perpendicular to the faces. The magnitude of the heat transfer rate, in kW, rounded off to the nearest integer, is _____

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The temperatures of two large parallel plates of equal emissivity are 900 K and 300 K. A reflection radiation shield of low emissivity and negligible conductive resistance is placed parallel between them. The steady-state temperature of the shield, in K, is

Your answerChoose one option.

759

559

659

859

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Hot oil at 110 °C heats water from 30 °C to 70 °C in a counter-current double-pipe heat exchanger. The flow rates of water and oil are 50 kg min

and 100 kg min

, respectively and their specific heat capacities are 4.2 kJ kg

°C

and 2.0 kJ kg

°C

, respectively. Assume the heat exchanger is at steady state. If the overall heat transfer coefficient is 200 W m

°C

, the heat transfer area in m

Your answerChoose one option.

17.9

1.1

5.2

35.2

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A solid slab of thickness

is initially at a uniform temperature

. At time

, the temperature of the top surface at

is increased to

, while the bottom surface at

is maintained at

for

. Assume heat transfer occurs only in the

-direction, and all thermal properties of the slab are constant. The time required for the temperature at

to reach 99% of its final steady value is

. If the thickness of the slab is doubled to

, and the time required for the temperature at

to reach 99% of its final steady value is

, then

Your answerChoose one option.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Match the quantities in Group 1 with their units in Group 2 listed in the table below.

Group 1	Group 2
P) Thermal conductivity	I) W·m⁻²K⁻¹
Q) Convective heat transfer coefficient	II) W·m⁻¹K⁻¹
R) Stefan-Boltzmann constant	III) W·K⁻¹
S) Heat capacity rate	IV) W·m⁻²K⁻⁴

Your answerChoose one option.

P-II, Q-I, R-IV, S-III

P-I, Q-II, R-III, S-IV

P-III, Q-IV, R-II, S-I

P-IV, Q-I, R-III, S-II

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A slab of thickness

, as shown in the figure below, has cross-sectional area

and constant thermal conductivity

and

are the temperatures at

and

, respectively. Which one of the following options is the CORRECT expression of the thermal resistance for steady-state one-dimensional heat conduction?

Diagram for Chemical Engineering question 22

Your answerChoose one option.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An isothermal jacketed continuous stirred tank reactor (CSTR) operating at 150 °C is shown in the figure below. The cold feed entering the system at 30 °C is preheated to a temperature

(

°C) using a heat exchanger

. This preheated feed is further heated to 150 °C using the utility heater

. The mass flow rate and heat capacity are same for all the process streams, and the overall heat transfer coefficient is independent of temperature. Which one of the following statements is the CORRECT action to take if it is desired to increase the value of

Diagram for Chemical Engineering question 27

Your answerChoose one option.

Increase both heat transfer area of

and heat duty of

Decrease both heat transfer area of

and heat duty of

Increase the heat transfer area of

and decrease the heat duty of

Decrease the heat transfer area of

and increase the heat duty of

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Given that

(in W·m

) is the total hemispherical emissive power of a surface maintained at a certain temperature, which of the following statements is/are CORRECT?

Your answerSelect all correct options. You can choose more than one.

does not depend on the direction of the emission.

depends on the viewer.

depends on the wavelength of the emission.

does not depend on the frequency of the emission.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Which of the following statements is/are CORRECT?

Your answerSelect all correct options. You can choose more than one.

Bond number includes surface tension.

Jakob number includes latent heat.

Prandtl number includes liquid-vapor density difference.

Biot number includes gravity.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A fluid is flowing steadily under laminar conditions over a thin rectangular plate at temperature

as shown in the figure below. The velocity and temperature of the free stream are

and

, respectively. When the fluid flow is only in the

-direction,

is the local heat transfer coefficient. Similarly, when the fluid flow is only in the

-direction,

is the corresponding local heat transfer coefficient. Use the correlation

for the local heat transfer coefficient, where, Nu, Re and Pr are the appropriate Nusselt, Reynolds and Prandtl numbers. The average heat transfer coefficients are defined as

and

. If

m and

m, the value of the ratio of

is ______ (in integer).

Diagram for Chemical Engineering question 54

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE CH Heat Transfer PYQs

Question 34

Question 37

Question 38

Question 39

Question 21

Question 22

Question 27

Question 30

Question 46

Question 54