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 6 of 21

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Q51.
A small body has a total emissive power of 4.5 kW/m². Determine the wavelength of emission maximum

a.

8.46 micron m

b.

7.46 micron m

c.

6.46 micron m

d.

5.46 micron m

Discuss
Answer: (d).5.46 micron m
Q52.
The sun emits maximum radiation of 0.52 micron meter. Assuming the sun to be a black body, Calculate the emissive ability of the sun’s surface at that temperature

a.

3.47 * 10⁷ W/m²

b.

4.47 * 10⁷ W/m²

c.

5.47 * 10⁷ W/m²

d.

6.47 * 10⁷ W/m²

Discuss
Answer: (b).5.47 * 10⁷ W/m²
Q53.
The law governing the distribution of radiant energy over wavelength for a black body at fixed temperature is referred to as

a.

Kirchhoff’s law

b.

Planck’s law

c.

Wein’s formula

d.

Lambert’s law

Discuss
Answer: (b).Planck’s law
Q54.
The Planck’s constant h has the dimensions equal to

a.

M L² T¯¹

b.

M L T¯¹

c.

M L T¯²

d.

M L T

Discuss
Answer: (a).M L² T¯¹
Q55.
Planck’s law is given by

a.

(E) b = 2 π c² h (Wavelength)¯⁵/[c h/k (Wavelength) T] – 2

b.

(E) b = π c² h [exponential [c h/k (Wavelength) T] – 3].

c.

(E) b = 2 π c² h (Wavelength)¯⁵/exponential [c h/k (Wavelength) T] – 1

d.

(E) b = 2 c² h (Wavelength)¯⁵/exponential [c h/k (Wavelength) T] – 6

Discuss
Answer: (c).(E) b = 2 π c² h (Wavelength)¯⁵/exponential [c h/k (Wavelength) T] – 1
Q56.
A furnace emits radiation at 2000 K. Treating it as a black body radiation, calculate the monochromatic radiant flux density at 1 micron m wavelength

a.

5.81 * 10⁷ W/m²

b.

4.81 * 10⁷ W/m²

c.

3.81 * 10⁷ W/m²

d.

2.81 * 10⁷ W/m²

Discuss
Answer: (d).2.81 * 10⁷ W/m²
Q57.
A metal sphere of surface area 0.0225 m² is in an evacuated enclosure whose walls are held at a very low temperature. Electric current is passed through resistors imbedded in the sphere causing electrical energy to be dissipated at the rate of 75 W. If the sphere surfaces temperature is measured to be 560 K, while in steady state, calculate emissivity of the sphere surface

a.

0.498

b.

0.598

c.

0.698

d.

0.798

Discuss
Answer: (b).0.598
Q58.
The Stefan-Boltzmann constant has units of

a.

kcal/m² hr K⁴

b.

kcal/m hr K⁴

c.

kcal/hr K⁴

d.

kcal/m² K⁴

Discuss
Answer: (a).kcal/m² hr K⁴
Q59.
According to Stefan-Boltzmann law of thermal radiation

a.

q = α A T

b.

q = α A T⁴

c.

q = α A T³

d.

q = α A T⁵

Discuss
Answer: (b).q = α A T⁴
Q60.
Calculate the radiant flux density from a black surface at 400 degree Celsius?

a.

1631.7 W/m²

b.

31.7 W/m²

c.

631.7 W/m²

d.

11631.7 W/m²

Discuss
Answer: (d).11631.7 W/m²
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