# Heat Transfer 3

Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Heat Transfer 3

Part 3: List for questions and answers of Heat Transfer

Q1.What is the purpose of using fins in a particular heat transfer system?
a) To decrease rate of heat transfer
b) To increase rate of heat transfer
c) To transfermaintain rate of heat at a constant rate
d) Cannot say

Q2.Temperature at the end tip of the fin having uniform cross-sectional area is
a) Maximum
b) Minimum
c) Similar to the heat generation temperature
d) Unpredictable

Q3.In the process of heat transfer through extended surfaces or fins, the entire surface area is at
a) The same constant temperature
b) Different temperatures
c) Maximum base temperature
d) Minimum temperature

Q4.What is the effect of thermal conductivity k on fin effectiveness?
a) Fin is effective for smaller value of thermal conductivity k
b) Fin is effective for larger value of thermal conductivity k
c) Thermal conductivity k does not affect the fin effectiveness
d) Cannot say

Q5.What is the effect of convective heat transfer coefficient h on fin effectiveness?
a) Fin is effective if the value of convective heat transfer coefficient h is small
b) Fin is effective if the value of convective heat transfer coefficient h is large
c) Fin effectiveness does not affected by the value of convective heat transfer
coefficient h
d) None of the above

Q6.Which medium of surrounding is better for fin effectiveness?
a) Gas medium
b) Liquid medium
c) Fins have same effectiveness in both the gas and liquid mediums
d) None of the above

Q7.For effective working of fins, the thickness of the fines should be
a) Large
b) Small
c) Thickness of fin does not affect the fin effectiveness
d) Unpredictable

Q8.Aluminum is used as a fin material because
a) It has higher convection heat transfer coefficient
b) It has higher thermal conductivity
c) It has lower convection heat transfer coefficient
d) It has lower thermal conductivity

Q9.In convection heat transfer energy transfer takes place between
a) Two solid surfaces connected physically
b) Solid surface and fluid system in motion
c) Both a. And b
d) None of the above

Q10.The convection heat transfer coefficient depends upon
a) The thermal properties of fluid
b) Geometry of the system
c) Characteristics of the fluid flow
d) All of the above

Q11.Which two processes are unitedly responsible in the transfer of heat between solid surface and surrounding fluid?
a) Conduction and convection
b) Conduction and mass transfer
c) Convection and mass transfer
d) None of the above

Q12.In a process of heat transfer by convection from a body to the surrounding fluid, the convection heat transfer coefficient
a) Stable over the entire surface of the body
b) Remains constant over the entire surface of the body
c) Does not remain constant over the entire surface of the body
d) None of the above

Q13.When the surface of a body is at higher temperature than the surrounding fluid, then the heat flows firstly from surface of the body to the adjacent layer of fluid by
a) Convection
b) Conduction
d) None of the above

Q14.What is hydro dynamically developed region in fluid flowing inside a pipe?
a) A region where velocity profile of the fluid is partially developed
b) A region where velocity profile of the fluid is fully developed
c) A region where velocity profile of the fluid changes according to the distance
d) None of the above

Q15.What is the ratio of the buoyancy force to the viscous force acting on a fluid called?
a) Prandtl number (Pr)
b) Reynolds number (Re)
c) Nusselt number (Nu)
d) Grashof number (Gr)

Q16.In natural convection, the Nusselt number (Nu) depends on
a) Pr and Re
b) Gr and Re
c) Gr and Pr
d) None of the above

Q17.If there are no externally induced flow velocities, then the Nusselt number (Nu) does not depend upon
a) Prandtl number (Pr)
b) Reynolds number (Re)
c) Grashof number (Gr)
d) None of the above

Q18.The Grashof number in natural convection plays same role as
a) Prandtl number (Pr) in forced convection
b) Reynolds number (Re) in forced convection
c) Nusselt number (Nu) in forced convection
d) None of the above

Q19.Heat transfer deals with the rate of
a) Work transfer
b) Temperature transfer
c) Energy transfer
d) None of the above

Q20.Which among the following has lowest thermal conductivity among the others?
a) Silver
b) Water
c) Mercury
d) Copper

Part 3: List for questions and answers of Heat Transfer