Transient Heat MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Transient Heat, 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 Transient Heat 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 Transient Heat mcq questions that explore various aspects of Transient Heat problems. Each MCQ is crafted to challenge your understanding of Transient Heat 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 Transient Heat 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 Transient Heat. 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 Transient Heat knowledge to the test? Let's get started with our carefully curated MCQs!

Transient Heat MCQs | Page 4 of 8

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Q31.
When the surface temperature variation inside a solid are periodic in nature, the profile of temperature variation with time may assume

a.

Triangular

b.

Linear

c.

Parabolic

d.

Hyperbolic

Discuss
Answer: (a).Triangular
Q32.
The surface temperature oscillates about the mean temperature level in accordance with the relation

a.

Ξ± S,T – Ξ± S,A = 2 sin (2 Ο€ n T)

b.

Ξ± S,T – Ξ± S,A = 5 sin (2 Ο€ n T)

c.

Ξ± S,T – Ξ± S,A = sin (2 Ο€ n T)

d.

Ξ± S,T – Ξ± S,A = 3 sin (2 Ο€ n T)

Discuss
Answer: (c).Ξ± S,T – Ξ± S,A = sin (2 Ο€ n T)
Q33.
The temperature variation of a thick brick wall during periodic heating or cooling follows a sinusoidal waveform. During a period of 24 hours, the surface temperature ranges from 25 degree Celsius to 75 degree Celsius. Workout the time lag of the temperature wave corresponding to a point located at 25 cm from the wall surface. Thermo-physical properties of the wall material are; thermal conductivity = 0.62 W/m K; specific heat = 450 J/kg K and density = 1620 kg/m³

a.

3.980 hour

b.

6.245 hour

c.

2.648 hour

d.

3.850 hour

Discuss
Answer: (b).6.245 hour
Q34.
A single cylinder 2-stroke engine operates at 1500 rpm. Calculate the depth where the temperature wave due to variation in cylinder is damped to 1% of its surface value. For the cylinder material, thermal diffusivity = 0.042 m²/hr

a.

0.1996 cm

b.

0.3887 cm

c.

0.2774 cm

d.

0.1775 cm

Discuss
Answer: (d).0.1775 cm
Q35.
The temperature distribution at a certain time instant through a 50 cm thick wall is prescribed by the relation

T = 300 – 500 x – 100 x² + 140x³

Where temperature t is in degree Celsius and the distance x in meters has been measured from the hot surface. If thermal conductivity of the wall material is 20 k J/m hr degree, calculate the heat energy stored per unit area of the wall

a.

4100 k J/hr

b.

4200 k J/hr

c.

4300 k J/hr

d.

4400 k J/hr

Discuss
Answer: (a).4100 k J/hr
Q36.
A large plane wall, 40 cm thick and 8 m² area, is heated from one side and temperature distribution at a certain time instant is approximately prescribed by the relation:

T = 80 – 60 x +12 x² + 25 x³ – 20 x⁴

Where temperature t is in degree Celsius and the distance x in meters. Make calculations for heat energy stored in the wall in unit time.

For wall material:
Thermal conductivity = 6 W/m K and thermal diffusivity = 0.02 m²/hr

a.

870.4 W

b.

345.6 W

c.

791.04 W

d.

238.5 W

Discuss
Answer: (c).791.04 W
Q37.
Which of the following has units of time constant?
(Where, P is density, A is area, c is specific heat and V is volume)

a.

p V/h A

b.

p c/h A

c.

p V c/h A

d.

V c/h A

Discuss
Answer: (c).p V c/h A
Q38.
β€œThermal radiation suffers no attenuation in a vacuum”. Choose the correct answer

a.

True

b.

False

c.

May be

d.

Can't say

Discuss
Answer: (a).True
Q39.
How does the body temperature falls or rises with time?

a.

Logarithmic

b.

Parabolic

c.

Linear

d.

Exponentially

Discuss
Answer: (d).Exponentially
Q40.
An iron billet (k = 65 W/m K) measuring 20 * 15 * 80 cm is exposed to a convective flow resulting in convection coefficient of 11.5 W/m² K. Determine the Biot number

a.

0.02376

b.

0.008974

c.

0.004563

d.

0.006846

Discuss
Answer: (d).0.006846
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