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 20 of 21

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Q191.
The intensity of normal radiation In is how much times the emissive power?

a.

1/π

b.

2/ π

c.

3/ π

d.

4/ π

Discuss
Answer: (a).1/π
Q192.
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
Q193.
Consider a deep-space probe constructed as 1 m diameter polished aluminum sphere. Estimate the equilibrium temperature that the probe reaches if the solar energy received is 300 W/m². For solar radiation, absorptivity of aluminum is 0.3 and the average emissivity appropriate for aluminum at low temperature is 0.04

a.

415.67 K

b.

315.67 K

c.

215.67 K

d.

115.67 K

Discuss
Answer: (b).315.67 K
Q194.
The total emissive power of the emitter with area d A and temperature T is given by

a.

E = 2 σ T⁴ d A

b.

E = 3 σ T⁴ d A

c.

E = σ T⁴ d A

d.

E = ½ σ T⁴ d A

Discuss
Answer: (c).E = σ T⁴ d A
Q195.
A black body of 0.2 m² area has an effective temperature of 800 K. Calculate the intensity of normal radiations

a.

1234.65 W/m² sr

b.

7396.28 W/m² sr

c.

3476.74 W/m² sr

d.

8739.43 W/m² sr

Discuss
Answer: (b).7396.28 W/m² sr
Q196.
The energy radiated out decreases with increases in α and becomes zero at an angle of

a.

45

b.

30

c.

0

d.

90

Discuss
Answer: (d).90
Q197.
Find the shape factor F 12 for the arrangement shown in the figure. The areas A 1 and A 2 are perpendicular but do not share the common edge

a.

0.03

b.

0.04

c.

0.05

d.

0.06

Discuss
Answer: (b).0.04
Q198.
Consider radiant heat exchange between two non-black parallel surfaces. The surface 1 emits radiant energy E 1 which strikes the surface 2. Identify the correct option

a.

The value of B is α E1

b.

The value of C is (1 – α1) E 1

c.

The value of D is (1 – α1) (1 – α2)² E 1

d.

The value of E is (1 – α1)² (1 – α2) E 1

Discuss
Answer: (c).The value of D is (1 – α1) (1 – α2)² E 1
Q199.
Two large parallel planes with emissivity 0.4 are maintained at different temperatures and exchange heat only by radiation. What percentage change in net radiative heat transfer would occur if two equally large radiation shields with surface emissivity 0.04 are introduced in parallel to the plates?

a.

65.1%

b.

75.1%

c.

85.1%

d.

95.1%

Discuss
Answer: (d).95.1%
Q200.
A blind cylindrical hole of 2 cm diameter and 3 cm length is drilled into a metal slab having emissivity 0.7. If the metal slab is maintained at 650 K, make calculations for the radiation heat escape from the hole

a.

7 W

b.

3 W

c.

1 W

d.

9 W

Discuss
Answer: (b).3 W
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