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Heat And Mass Transfer MCQ Questions & Answers | Mechanical Engineering

Learn Heat And Mass Transfer MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Heat And Mass Transfer MCQ question is the important chapter for a Mechanical Engineering and GATE students. Page-5 section-2

Each section contains 100 MCQs on Heat and Mass Transfer .
41
Which of the following is a case of steady state heat transfer?
Discuss
Answer & Solution
Answer: Option D
Solution:
IC Engine- Forced Convection
Air Preheaters- Air preheaters use the hot exhaust gas from the furnace to heat the incoming combustion air
Heating of building in winter-Conduction is heat traveling through a solid material. On hot days, heat is conducted into your home through the roof, walls, and windows.
42
Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without affecting the intervening medium.
Discuss
Answer & Solution
Answer: Option B
Solution:
Radiation is the process of heat transfer in which heat flows from a Hot body to cold body in a straight line, without affecting the intervening medium.
43
Fourier's law of heat conduction gives the heat flow for
Discuss
Answer & Solution
Answer: Option C
Solution:
Fourier's law of heat conduction is valid for One dimensional cases only
Fourier equation is valid for all matter solid, liquid or gas. The vector expression indicating that heat flow rate is normal to an isotherm and is in the direction of decreasing temperature.
44
In a shell and tube heat exchanger, baffles are provided on the shell side to
Discuss
Answer & Solution
Answer: Option D
Solution:
In a shell and tube heat exchanger, baffles are provided on the shell side to Improve heat transfer And Provide support for tubes and Prevent stagnation of shell side fluid
45
A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is
Discuss
Answer & Solution
Answer: Option A
Solution:
tm = mean temperature difference between the two fluids for counter flow heat exchanger
tm = th1 - tc2 = th2 - tc1
tm = th2 - tc1 = 60 - 40 = 20.
46
If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ and λ + dλ is represented by (eλ.dλ), then eλ is called
Discuss
Answer & Solution
Answer: Option B
Solution:
If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ and λ + dλ is represented by (eλ.dλ), then eλ is called Emissive power.
47
The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as
Discuss
Answer & Solution
Answer: Option B
Solution:
Free convection heat transfer is the transfer of heat due to movement of liquid and air molecules without external source such as a pump or fan.
It occurs due to forces generated by density differences caused by temperature difference.
48
The process of heat transfer from one particle of the body to another by the actual motion of the heated particles, is called
Discuss
Answer & Solution
Answer: Option B
Solution:
When a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along. This type of heat transfer is called convection.
49
Fourier's law of heat conduction is valid for
Discuss
Answer & Solution
Answer: Option A
Solution:
Fourier's law of heat conduction is valid for One dimensional cases only
Fourier equation is valid for all matter solid, liquid or gas. The vector expression indicating that heat flow rate is normal to an isotherm and is in the direction of decreasing temperature.
50
According to Newton's law of cooling, the heat transfer from a hot body to a cold body is
Discuss
Answer & Solution
Answer: Option D
Solution:
Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its surroundings.