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 14 of 21

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Q131.
What is the value of grey body factor for concentric cylinders?

a.

3/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)].

b.

4/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)].

c.

1/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)].

d.

2/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)].

Discuss
Answer: (c).1/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)].
Q132.
The net rate at which the radiation leaves the surface is given by

a.

e (E b – J)/1 – 4 e

b.

e (E b – J)/1 – 3 e

c.

e (E b – J)/1 – 2 e

d.

e (E b – J)/1 – e

Discuss
Answer: (d).e (E b – J)/1 – e
Q133.
A ring (E = 0.85) of 8 cm inner and 16 cm outer diameter is placed in a horizontal plane. A small element (E = 0.7) of 1 cm² is placed concentrically 8 cm vertically below the center of the ring. The temperature of the ring is 800 K and that of small area is 400 K. Find the radiant heat gain by the small ring

a.

– 10.59 J/hour

b.

– 11.59 J/hour

c.

– 12.59 J/hour

d.

– 13.59 J/hour

Discuss
Answer: (b).– 11.59 J/hour
Q134.
Two opposed, parallel, infinite planes are maintained at 420 K and 480 K. Calculate the net heat flux between these planes if one has an emissivity of 0.8 and other an emissivity of 0.7

a.

534.86 W/m²

b.

634.86 W/m²

c.

734.86 W/m²

d.

834.86 W/m²

Discuss
Answer: (c).734.86 W/m²
Q135.
The total radiant energy incident upon a surface per unit time per unit area is known as

a.

Shape factor

b.

Radiosity

c.

Radiation

d.

Irradiation

Discuss
Answer: (d).Irradiation
Q136.
Which one of the following is true for opaque non-black surface?

a.

J = E +2 p G

b.

J = E + p G

c.

J = 2 E + p G

d.

J = ½ E + p G

Discuss
Answer: (b).J = E + p G
Q137.
A radiation shield should

a.

Have high transmissivity

b.

Absorb all the radiations

c.

Have high reflexive power

d.

Partly absorb and partly transmit the incident radiation

Discuss
Answer: (c).Have high reflexive power
Q138.
Radiation shield are used between the emitting surfaces such that

a.

To reduce overall heat transfer

b.

To increase overall heat transfer

c.

To increase density

d.

To reduce density

Discuss
Answer: (a).To reduce overall heat transfer
Q139.
Which of the following can be used as a radiating shield?

a.

Carbon

b.

Thin sheets of aluminum

c.

Iron

d.

Gold

Discuss
Answer: (b).Thin sheets of aluminum
Q140.
Determine the net radiant heat exchange per m 2 area for two infinite parallel plates held at temperature of 800 K and 500 K. Take emissivity as 0.6 for the hot plate and 0.4 for the cold plate

a.

6200 W/m²

b.

7200 W/m²

c.

8200 W/m²

d.

9200 W/m²

Discuss
Answer: (a).6200 W/m²
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