Heat Transfer Online Quiz Questions and Answers

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1. Unit of thermal conductivity in M.K.S. units is _____.
kcal/kg m2 °C	kcal-m/hr m2 °C
kcal/hr m2 °C	kcal-m/hr °C

2. Unit of thermal conductivity in S.I. units is ______.
J/m2 sec	J/m °K sec
W/m °K	(a) and (c) above

3. Thermal conductivity of solid metals with rise in temperature normally
increases	decreases
remains constant	may increase or decrease depending on temperature

4. Thermal conductivity of non-metallic amor-phous solids with decrease in temperature
increases	decreases
remains constant	may increase or decrease depending on temperature

5. Heat transfer takes place as per
zeroth law of thermodynamics	first law of thermodynamic
second law of the thermodynamics	Kirchoff's law (e) Stefan's law

6. When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
conduction	convection
radiation	conduction and convection

7. When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by
conduction	convection
radiation	conduction and convection

8. Sensible heat is the heat required to _____.
change vapour into liquid	change liquid into vapour
increase the temperature of a liquid of vapour	convert water into steam and superheat it

9. The insulation ability of an insulator with the presence of moisture would _____.
increase	decrease
remain unaffected	may increase/decrease depending on temperature and thickness of insulation

10. When heat is Transferred by molecular collision, it is referred to as heat transfer by ___.
conduction	convection
radiation	scattering

11. Heat transfer in liquid and gases takes place by _____.
conduction	convection
radiation	conduction and convection

12. Which of the following is the case of heat transfer by radiation
blast furnace	heating of building
cooling of parts in furnace	heat received by a person from fireplace

13. Heat is closely related with _____.
liquids	energy
temperature	entropy

14. Pick up tne wrong case. Heat flowing from one side to other depends directly on _____.
face area	time
thickness	temperature difference

15. Metals are good conductors of heat because
their atoms collide frequently	thier atoms-are relatively far apart
they contain free electrons	they have high density

16. Which of the following is a case of steady state heat transfer
I.C. engine	air preheaters
heating of building in winter	none of the above

17. Total heat is the heat required to _____.
change vapour into liquid	change liquid into vapour
increase the temperature of a liquid or vapour	convert water into steam and superheat it

18. Cork is a good insulator because it has _____.
free electrons	atoms colliding frequency
low density	porous body

19. Thermal conductivity of water in general with rise in temperature
increases	decreases
remains constant	may increase or decrease depending on temperature

20. Thermal conductivity of water at 20°C is of the order of _____.
0.1	0.23
0.42	0.51