Heat Transfer Questions and Answers – Steady Flow of Heat Along a Rod

«
»

This set of Heat Transfer Interview Questions & Answers focuses on “Steady Flow of Heat Along a Rod”.

1. Which one is true regarding rectangular fin?
a) A C = b δ and P = 2(b + δ)
b) A C = 2 b δ and P = 2(b + δ)
c) A C = 3 b δ and P = 2(b + δ)
d) A C = 4 b δ and P = 2(b + δ)
View Answer

Answer: a
Explanation: For rectangle, A = (length) (breadth). Where, b = width and δ = thickness.

2. Analysis of heat flow from the finned surface is made with the following assumptions
(i) Uniform heat transfer coefficient, h over the entire fin surface
(ii) No heat generation within the fin generation
(iii) Homogenous material
Identify the correct option
a) i only
b) i and ii only
c) i, ii and iii
d) ii only
View Answer

Answer: c
Explanation: The knowledge of temperature distribution is necessary for their optimum design with regard to size and weight.

3. If heat conducted into the element at plane x is Q X = – k A C (d t/d x) X. Then heat conducted out of the element at plane (x + d x) is
a) – 2k A C d/d x (t + d t/d x (d x))
b) – k A C d/d x (t + d t/d x (d x))
c) – 3k A C d/d x (t + d t/d x (d x))
d) – 4k A C d/d x (t + d t/d x (d x))
View Answer

Answer: b
Explanation: Heat conducted out of the element is – [k A C (d t/d x) X + d x].
Note: Join free Sanfoundry classes at Telegram or Youtube
advertisement
advertisement

4. A heating unit is made in the form of a vertical tube of 50 mm outside diameter and 1.2 m height. The tube is fitted with 20 steel fins of rectangular section with height 40 mm and thickness 2.5 mm. The temperature at the base of fin is 75 degree Celsius, the surrounding air temperature is 20 degree Celsius and the heat transfer coefficient between the fin as well as the tube surface and the surrounding air is 9.5 W/m2 K. If thermal conductivity of the fin material is 55 W/m K, find the amount of heat transferred from the tube without fin
a) 98.44 W
b) 88.44 W
c) 78.44 W
d) 68.44 W
View Answer

Answer: a
Explanation: Q = h A d t = h (π d 0 H) (t 0 – t INFINITY).

5. The general solution of linear and homogenous differential equation (second form) is of the form
a) γ = C 1 e 2 m x + C 2 e – m x
b) γ = C 1 e 3m x + C 2 e – m x
c) γ = C 1 e 4 m x + C 2 e – m x
d) γ = C 1 e m x + C 2 e – m x
View Answer

Answer: d
Explanation: It should contain m x and – m x term.
Take Heat Transfer Mock Tests - Chapterwise!
Start the Test Now: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

6. For steady flow of heat along a rod, the general equation is
d2α/dx 2 – m 2 α = 0
The value of constant m is
a) (h P/k A C)
b) (h P/k A C) 3/2
c) (h P/k A C) 1/2
d) (h P/k A C) 2
View Answer

Answer: c
Explanation: This provides a general form of the energy equation for one dimensional heat flow.

7. In convection from the tip, we introduced a factor known as
a) Fin length
b) Correction length
c) No fin length
d) Radial length
View Answer

Answer: b
Explanation: Just for simplicity we replace fin length by correction length.
advertisement

8. Find the value of corrected length for rectangular fin?
Where, b is width and t is length of the fin
a) L C = L + b t/2 (b + t)
b) L C = L + b t/ (b + t)
c) L C = L + 2 (b + t)
d) L C = L + b t
View Answer

Answer: a
Explanation: For rectangle, area = t b.

9. Which one is true for the spine?
a) A C = π d 2/4 and P = 4 π d
b) A C = π d 2/4 and P = 3 π d
c) A C = π d 2/4 and P = π d
d) A C = π d 2/4 and P = 2 π d
View Answer

Answer: c
Explanation: A spine is a pin fin.
advertisement

10. In convection from the tip what is the value of correction length?
a) L C = A C/P
b) L C = L + A C
c) L C = L + P
d) L C = L + A C/P
View Answer

Answer: d
Explanation: It should contain all the three terms i.e. L, A and P.

Sanfoundry Global Education & Learning Series – Heat Transfer.

To practice all areas of Heat Transfer for interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & technical discussions at Telegram SanfoundryClasses.