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 19 of 21

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Q181.
The net heat interchange between non-black bodies at temperature T 1 and T 2 is given by

a.

fโ‚โ‚‚ Fโ‚โ‚‚ ฯƒ (Tโ‚โด โ€“ Tโ‚‚โด)

b.

fโ‚โ‚‚ Fโ‚โ‚‚ Aโ‚ ฯƒ (Tโ‚โด โ€“ Tโ‚‚โด)

c.

fโ‚โ‚‚ Aโ‚ ฯƒ (Tโ‚โด โ€“ Tโ‚‚โด)

d.

Fโ‚โ‚‚ Aโ‚ ฯƒ (Tโ‚โด โ€“ Tโ‚‚โด)

Discuss
Answer: (b).fโ‚โ‚‚ Fโ‚โ‚‚ Aโ‚ ฯƒ (Tโ‚โด โ€“ Tโ‚‚โด)
Q182.
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
Q183.
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
Q184.
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
Q185.
What is the value of grey body factor for concentric cylinders?

a.

3/ [1 โ€“ e 1/e 1 + 1 + 1 โ€“ e 2/e 2 (A 1/A 2)].

b.

4/ [1 โ€“ e 1/e 1 + 1 + 1 โ€“ e 2/e 2 (A 1/A 2)].

c.

1/ [1 โ€“ e 1/e 1 + 1 + 1 โ€“ e 2/e 2 (A 1/A 2)].

d.

2/ [1 โ€“ e 1/e 1 + 1 + 1 โ€“ e 2/e 2 (A 1/A 2)].

Discuss
Answer: (c).1/ [1 โ€“ e 1/e 1 + 1 + 1 โ€“ e 2/e 2 (A 1/A 2)].
Q186.
The net rate at which the radiation leaves the surface is given by

a.

e (E b โ€“ J)/1 โ€“ 4 e

b.

e (E b โ€“ J)/1 โ€“ 3 e

c.

e (E b โ€“ J)/1 โ€“ 2 e

d.

e (E b โ€“ J)/1 โ€“ e

Discuss
Answer: (d).e (E b โ€“ J)/1 โ€“ e
Q187.
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.

โ€“ 10.59 J/hour

b.

โ€“ 11.59 J/hour

c.

โ€“ 12.59 J/hour

d.

โ€“ 13.59 J/hour

Discuss
Answer: (b).โ€“ 11.59 J/hour
Q188.
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
Q189.
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
Q190.
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
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