Food Engineering Questions and Answers – Unit Operations – Heat Transfer by Conduction

This set of Food Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Unit Operations – Heat Transfer by Conduction”.

1. ‘a’ refers to Steady state heat transfer & ‘b’ refers to unsteady state heat transfer
‘a’ refers to ______ and ‘b’ refers to _____
a) Steady state heat transfer, Unsteady state heat transfer
b) Unsteady state heat transfer, Steady state heat transfer
c) None of the mentioned
d) All of the mentioned
View Answer

Answer: a
Explanation: ‘a’ refers to Steady state heat transfer and ‘b’ refers to unsteady state heat transfer.

2. The equation

dq/dA= (k(-dT))/dx is called _____ a) Kirchhoff’s law of conduction b) Fourier’s law conduction c) Kirchhoff’s & Fourier’s law conduction d) None of the mentioned View Answer
Answer: b Explanation: The equation dq/dA= (k(-dT))/dx is called Fourier’s law conduction.

3. Statement 1: The heat transfer co-efficient in ice is four times that of water.
Statement 2: k in conductance is for thermal conductivity.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: b
Explanation: Both the statements are true.
advertisement
advertisement

4. Frozen foods have a higher transfer co-efficient hence they lose heat faster than other food items when exposed to the outside environment.
a) True
b) False
View Answer

Answer: a
Explanation: Frozen foods have a higher transfer co-efficient hence they lose heat faster than other food items when exposed to the outside environment.

5. Statement 1: When the average radius gives an error, log mean radius is used.
Statement 2: Log mean radius is given by rL= ( r0– ri )/(ln(r0/ri))
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: b
Explanation: Both the statements are true.
Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

6. Statement 1: α=k/(ρCp)
Statement 2: α stands for thermal conductivity.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: a
Explanation: α=k/(ρCp). α stands for thermal diffusivity.

7. Statement 1: NFo stands for Fourier number.
Statement 2: NFo= (αtT)/s2
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: b
Explanation: Both the statements pertaining to Fourier number are true.
advertisement

8. NFo= (αtT)/s2. Here ‘s’ stands for half slab thickness. Based on this data, ‘s’ for a chapatti/ dosa will be _____
a) Half slab thickness
b) Full slab thickness
c) One and a half slab thickness
d) Double slab thickness
View Answer

Answer: b
Explanation: ‘s’ for a chapatti/ dosa will be Full slab thickness. This is because ‘s’ equals half slab thickness only when heating takes place from both sides. But, for a chapatti/ dosa, heating takes place only from one end hence‘s’ becomes ‘2s’.

9. _____ is the equation for unsteady state heat conduction through solid materials.
a) dT/dx= α (d2 T)/ (dt)2
b) dT/dx= α (d2 T)/ (dx)2
c) dT/dt= α (d2 T)/ (dx)2
d) dT/dt= α (d2 T)/ (dt)2
View Answer

Answer: c
Explanation: dT/dt= α (d2 T)/ (dx)2 is the equation for unsteady state heat conduction through solid materials.
advertisement

10. For a copper pipe, k = 0.3534, temperature difference = 60, B = 0.0125 and A = 850. What is the value of q?
a) 1442 W
b) 1442 kW
c) 1565 W
d) 1565 kW
View Answer

Answer: b
Explanation: q=kA ∆T/B.

Sanfoundry Global Education & Learning Series – Food Engineering.

To practice all areas of Food Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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 & discussions at Telegram SanfoundryClasses.