Heat Radiation MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Heat Radiation, a fundamental topic in the field of Heat Transfer. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Heat Radiation MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of Heat Radiation mcq questions that explore various aspects of Heat Radiation problems. Each MCQ is crafted to challenge your understanding of Heat Radiation principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace Heat Transfer tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Heat Radiation MCQs are your pathway to success in mastering this essential Heat Transfer topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of Heat Radiation. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

So, are you ready to put your Heat Radiation knowledge to the test? Let's get started with our carefully curated MCQs!

Heat Radiation MCQs | Page 18 of 21

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Q171.
The furnace of a boiler is laid from fire clay brick with outside lagging from the plate steel, the distance between the two is quite small compared with the size of the furnace. The brick setting is at an average temperature of 365 K whilst the steel lagging is at 290 K. Calculate the radiant heat flux. Assume the following emissivity values

For brick = 0.85
For steel = 0.65

a.

352.9 W/m²

b.

452.9 W/m²

c.

552.9 W/m²

d.

652.9 W/m²

Discuss
Answer: (a).352.9 W/m²
Q172.
Two black discs each of diameter 50 cm are placed parallel to each other concentrically at a distance of one meter. The discs are maintained at 1000 K and 500 K. Calculate the heat flow between the discs when no other surface is present

a.

317.27 W

b.

417.27 W

c.

517.27 W

d.

617.27 W

Discuss
Answer: (b).417.27 W
Q173.
Two black discs each of diameter 50 cm are placed parallel to each other concentrically at a distance of one meter. The discs are maintained at 1000 K and 500 K. Calculate the heat flow between the discs when the disks are connected by a cylindrical black no-flux surface

a.

2417.68 W

b.

3417.68 W

c.

4417.68 W

d.

5417.68 W

Discuss
Answer: (d).5417.68 W
Q174.
A cavity in the shape of a frustum of a cone has diameter 30 cm and 60 cm and the height is 80 cm. If the cavity is maintained at temperature of 800 K, determine the heat loss from the cavity when the smaller diameter is at the bottom

a.

6577 W

b.

2367 W

c.

8794 W

d.

3675 W

Discuss
Answer: (a).6577 W
Q175.
A conical cavity of base diameter 15 cm and height 20 cm has inside surface temperature 650 K. If emissivity of each surface is 0.85, determine the net radiative heat transfer from the cavity

a.

168.3 W

b.

158.3 W

c.

148.3 W

d.

138.3 W

Discuss
Answer: (a).168.3 W
Q176.
The reciprocity theorem states that (Where symbols have their usual meanings)

a.

F 12 = F 21

b.

A 1 F 12 = A 2 F 21

c.

A 1 F 21 = A 2 F 12

d.

A 2 F 21 = A 1 F 12

Discuss
Answer: (b).A 1 F 12 = A 2 F 21
Q177.
Two radiating surface A 1 = 6 m² and A 2 = 4 m² have shape factor F 12 = 0.1. Then the shape factor F 21 will be

a.

0.12

b.

0.18

c.

0.15

d.

0.10

Discuss
Answer: (c).0.15
Q178.
What is the value of shape factor for two infinite parallel surfaces separated by a distance x?

a.

0

b.

1

c.

x

d.

Infinity

Discuss
Answer: (b).1
Q179.
What is the shape factor of a sphere of diameter d inside a cubical box of length l = d?

a.

ฯ€/6

b.

2 ฯ€/6

c.

ฯ€/3

d.

ฯ€/4

Discuss
Answer: (a).ฯ€/6
Q180.
What is the shape factor of hemispherical surface closed by a plane surface of diameter d?

a.

0

b.

1.5

c.

1

d.

0.5

Discuss
Answer: (d).0.5
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