# Heat Transfer MCQ’s – Heat Transfer Coefficient

1 - Question

Which one is having highest value of overall heat transfer coefficient?
a) Steam condensers
b) Feed water heaters
c) Alcohol condensers
d) Steam
View Answer Answer: b
Explanation: Overall heat transfer coefficient for feed water heaters is 8500 W/m2 K while that of steam, alcohol condensers and ammonia condensers are 5000 W/m2 K, 630 W/m2 K and 1400 W/m2 K.

2 - Question

What is the value of overall heat transfer coefficient for air to heavy tars and liquid?
a) As low as 45 W/m2 K
b) As low as 40 W/m2 K
c) As low as 35 W/m2 K
d) As low as 30 W/m2 K
View Answer Answer: a
Explanation: It is an incompressible fluid which has constant volume independent of pressure.

3 - Question

What is the value of overall heat transfer coefficient for air to low viscosity liquid?
a) As high as 900 W/m2 K
b) As high as 800 W/m2 K
c) As high as 700 W/m2 K
d) As high as 600 W/m2 K
View Answer Answer: d
Explanation: It is made up of tiny vibrating particles of matter which are held together by intermolecular bonding.

4 - Question

Which one is having lowest value of overall heat transfer coefficient?
a) Steam
b) Air condensers
c) Air to heavy tars
d) Ammonia condensers
View Answer Answer: c
Explanation: Overall heat transfer coefficient for air to heavy tars is 45 W/m2 K while that of steam, air condensers and ammonia condensers are 340 W/m2 K, 780 W/m2 K and 1400 W/m2 K.

5 - Question

What is the value of overall heat transfer coefficient for air condensers?
a) 350-780 W/m2 K
b) 250 -900 W/m2 K
c) 200-350 W/m2 K
d) 200-1950 W/m2 K
View Answer Answer: a
Explanation: It consists of an air coil which is used to remove heat from fluids.

6 - Question

Which one is having highest value of overall heat transfer coefficient?
a) Steam
b) Alcohol condensers
c) Air condensers
d) Air to various gases
View Answer Answer: c
Explanation: Overall heat transfer coefficient for air condensers is 780 W/m2 K while that of steam, alcohol condensers and air to various gases are 340 W/m2 K, 700 W/m2 K and 550 W/m2 K.

7 - Question

What is the value of overall heat transfer coefficient ammonia condensers?
a) 800-1400 W/m2 K
b) 200-750 W/m2 K
c) 250-2500 W/m2 K
d) 1500-1750 W/m2 K
View Answer Answer: a
Explanation: It is an electrical device that stores a vast amount of energy.

8 - Question

Which one is having the lowest value of overall heat transfer coefficient?
a) Air condensers
b) Air to low viscosity liquids
c) Steam condensers
d) Feed water heaters
View Answer Answer: b
Explanation: Overall heat transfer coefficient for air condensers is 780 W/m2 K while that of steam condensers, air to low viscosity liquids and feed water heaters are 5000 W/m2 K, 600 W/m2 K and 8500 W/m2 K.

9 - Question

What is the value of overall heat transfer coefficient for steam condensers?
a) 200-9000 W/m2 K
b) 3000-5500 W/m2 K
c) 2000-9500 W/m2 K
d) 1500-5000 W/m2 K
View Answer Answer: d
Explanation: It is a rotating machine similar to a motor used to control power flow in electric power transmission.

10 - Question

Which one is having highest value of overall heat transfer coefficient?
a) Feed water heaters
b) Steam condensers
c) Alcohol condensers
d) Ammonia condensers
View Answer Answer: a
Explanation: Overall heat transfer coefficient for feed water heaters is 8500 W/m2 K while that of steam condensers, alcohol condensers and ammonia condensers are 5000 W/m2 K, 700 W/m2 K and 1400 W/m2 K.