Heat Transfer From Extended Surfaces MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Heat Transfer From Extended Surfaces, 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 Transfer From Extended Surfaces 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 Transfer From Extended Surfaces mcq questions that explore various aspects of Heat Transfer From Extended Surfaces problems. Each MCQ is crafted to challenge your understanding of Heat Transfer From Extended Surfaces 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 Transfer From Extended Surfaces MCQs are your pathway to success in mastering this essential Heat Transfer topic.

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Heat Transfer From Extended Surfaces MCQs | Page 3 of 8

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Q21.
If fin is sufficiently thin, so heat flows pertains to

a.

One dimensional heat conduction

b.

Two dimensional heat conduction

c.

Three dimensional heat conduction

d.

No heat flow is there

Discuss
Answer: (a).One dimensional heat conduction
Q22.
If heat dissipation for one fin is given by 377.45 k J/hour, then what is the heat dissipation for 12 fins?

a.

7529.4 k J/hour

b.

6529.4 k J/hour

c.

5529.4 k J/hour

d.

4529.4 k J/hour

Discuss
Answer: (d).4529.4 k J/hour
Q23.
In order to achieve maximum heat dissipation the fin should be designed in such a way that has a

a.

Maximum lateral surface towards the tip side of fin

b.

Minimum lateral surface near the center line

c.

Maximum lateral surface at the root side of fin

d.

Maximum lateral surface near the center of fin

Discuss
Answer: (c).Maximum lateral surface at the root side of fin
Q24.
A steel rod (k = 30 W/m degree) 1 cm in diameter and 5 cm long protrudes from a wall which is maintained at 10 degree Celsius. The rod is insulated at its tip and is exposed to an environment with h = 50 W/m² degree and t a = 30 degree Celsius. Calculate the rate of heat dissipation

a.

2.658 W

b.

3.658 W

c.

4.658 W

d.

5.658 W

Discuss
Answer: (b).3.658 W
Q25.
On a heat transfer surface, fins are provided to

a.

Increase turbulence in flow for enhancing heat transfer

b.

Increase temperature gradient so as to enhance heat transfer

c.

Pressure drop of the fluid should be minimized

d.

Surface area is maximum to promote the rate of heat transfer

Discuss
Answer: (d).Surface area is maximum to promote the rate of heat transfer
Q26.
In heat dissipation from an infinitely long fin, the boundary conditions are

a.

t = t0 at x = infinity and t = ta at x = 0

b.

t = t0 at x = 0 and t = ta at x = infinity

c.

t = t0 at x = 0 and t = ta at x = 0

d.

t = t0 at x = infinity and t = ta at x = infinity

Discuss
Answer: (b).t = t0 at x = 0 and t = ta at x = infinity
Q27.
The temperature distribution in case of infinitely long fin is

a.

t – t a/t₀ – t a = mx

b.

t – t a/t₀ – t a = -mx

c.

t – t a/t₀ – t a = e-m x

d.

t – t a/t₀ – t a = log (m x)

Discuss
Answer: (c).t – t a/t₀ – t a = e-m x
Q28.
The rate of heat transfer in case of infinitely long fin is given by

a.

(h P k A)^1/2 (t₀ – t a)

b.

(h P A)^1/2 (t₀ – t a)

c.

(P k A)^1/2 (t₀ – t a)

d.

(h k A)^1/2 (t₀ – t a)

Discuss
Answer: (a).(h P k A)^1/2 (t₀ – t a)
Q29.
Let us say there are two rods having same dimensions, one made of brass (k = 85W/m K) and the other of copper (k = 375W/m K), having one of their ends inserted into a furnace. At a section 10.5 cm away from the furnace, the temperature of brass rod is 120 degree Celsius. Find the distance at which the same temperature would be reached in the copper rod? Both ends are exposed to the same environment

a.

12.54 cm

b.

45.87 cm

c.

12.34 cm

d.

22.05 cm

Discuss
Answer: (d).22.05 cm
Q30.
Three rods, one made of silver (l = 420W/m K), second made of aluminum (k = 210W/m K) and the third made of iron (k = 70W/m K) are coated with a uniform layer of wax all around. The rods are placed vertically in a boiling water bath with 250 mm length of each rod projecting outside. If all the rods are having following dimensions i.e. diameter = 15 mm and length = 300 mm and have identical surface coefficient 12.5W/ m² K, work out the ratio of lengths up to which wax will melt on each rod

a.

2.45:1:1.732

b.

1.732:1:2.45

c.

2.45:1.732:1

d.

1.732:1:2.45

Discuss
Answer: (c).2.45:1.732:1
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