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 13 of 21

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Q121.
Interchange factor for body 1 completely enclosed by body 2 (body 1 is large) is given by

a.

2/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

b.

1/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

c.

4/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

d.

3/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

Discuss
Answer: (b).1/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].
Q122.
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
Q123.
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
Q124.
Interchange factor for infinitely long concentric cylinders is given by

a.

1/ [A₁/A₂ (1/E₂ – 1)].

b.

[1/E₁ + A₁/A₂ (1/E₂ – 1)].

c.

2/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

d.

1/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].

Discuss
Answer: (d).1/ [1/E₁ + A₁/A₂ (1/E₂ – 1)].
Q125.
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
Q126.
What is the geometric factor for concentric spheres?

a.

0.85

b.

0.33

c.

1

d.

0.95

Discuss
Answer: (c).1
Q127.
The net heat interchange between non-black bodies at temperature T 1 and T 2 is given by

a.

f₁₂ F₁₂ σ (T₁⁴ – T₂⁴)

b.

f₁₂ F₁₂ A₁ σ (T₁⁴ – T₂⁴)

c.

f₁₂ A₁ σ (T₁⁴ – T₂⁴)

d.

F₁₂ A₁ σ (T₁⁴ – T₂⁴)

Discuss
Answer: (b).f₁₂ F₁₂ A₁ σ (T₁⁴ – T₂⁴)
Q128.
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 and temperature of ambient air is 300 K. What thickness of cork (k = 0.03 W/m degree) would be required if the same insulating effect is to be achieved by the use of cork?

a.

26.8 cm

b.

25.8 cm

c.

24.8 cm

d.

23.8 cm

Discuss
Answer: (a).26.8 cm
Q129.
The total radiant energy leaving a surface per unit time per unit surface area is represented by

a.

Radiation

b.

Radiosity

c.

Irradiation

d.

Interchange factor

Discuss
Answer: (b).Radiosity
Q130.
Determine the radiant heat flux between two closely spaced, black parallel plates radiating only to each other if their temperatures are 850 K and 425 K. The plates have an area of 4 m²

a.

.040

b.

.030

c.

.020

d.

.010

Discuss
Answer: (d)..010
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