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 17 of 21

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Q161.
The plane angle is defined by a region by the rays of a circle, and is measured as

a.

3 L/ r

b.

2 L/ r

c.

L/ r

d.

4 L / r

Discuss
Answer: (c).L/ r
Q162.
When the incident surface is a sphere, the projection of surface normal to the line of propagation is the silhouette disk of the sphere which is a circle of the diameter of

a.

Parabola

b.

Sphere

c.

Triangle

d.

Hyperbola

Discuss
Answer: (b).Sphere
Q163.
If I n denotes the normal intensity and I ฮฑ represents the intensity at angle ฮฑ, then

a.

I ฮฑ = 2 I n cos ฮฑ

b.

I ฮฑ = 3 I n cos ฮฑ

c.

I ฮฑ = 4 I n cos ฮฑ

d.

I ฮฑ = I n cos ฮฑ

Discuss
Answer: (d).I ฮฑ = I n cos ฮฑ
Q164.
The intensity of normal radiation In is how much times the emissive power?

a.

1/ฯ€

b.

2/ ฯ€

c.

3/ ฯ€

d.

4/ ฯ€

Discuss
Answer: (a).1/ฯ€
Q165.
A small surface emits diffusively, and measurements indicate that the total intensity associated with emission in the normal direction I n = 6500 W/square m sr. The emitted radiation is intercepted by three surfaces. Mark calculations for intensity associated with emission

a.

3500 W/m² sr

b.

4500 W/m² sr

c.

5500 W/m² sr

d.

6500 W/m² sr

Discuss
Answer: (d).6500 W/m² sr
Q166.
Interchange factor for body 1 completely enclosed by body 2 (body 1 is large) is given by

a.

2/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

b.

1/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

c.

4/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

d.

3/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

Discuss
Answer: (b).1/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].
Q167.
A thermos flask has a double walled bottle and the space between the walls is evacuated so as to reduce the heat flow. The bottle surfaces are silver plated and the emissivity of each surface is 0.025. If the contents of the bottle are at 375 K, find the rate of heat loss from the thermos bottle to the ambient air at 300 K

a.

5.38 W

b.

6.38 W

c.

7.38 W

d.

8.38 W

Discuss
Answer: (d).8.38 W
Q168.
A 250 mm by 250 mm ingot casting, 1.5 m high and at 1225 K temperature, is stripped from its mold. The casting is made to stand on end on the floor of a large foundry whose wall, floor and roof can be assumed to be at 300 K temperature. Make calculation for the rate of radiant heat interchange between the casting and the room. The casting material has an emissivity of 0.85

a.

161120 W

b.

171120 W

c.

181120 W

d.

191120 W

Discuss
Answer: (b).171120 W
Q169.
Interchange factor for infinitely long concentric cylinders is given by

a.

1/ [Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

b.

[1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

c.

2/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

d.

1/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].

Discuss
Answer: (d).1/ [1/Eโ‚ + Aโ‚/Aโ‚‚ (1/Eโ‚‚ โ€“ 1)].
Q170.
What is the geometric factor for infinitely long concentric cylinders?

a.

1

b.

0.5

c.

0.33

d.

0.75

Discuss
Answer: (a).1
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