heat transfer objective questions with answers part2

Q1. Unit of thermal conductivity in M.K.S. units is
(A) kcal/kg m2 °C
(B) kcal-m/hr m2 °C
(C) kcal/hr m2 °C
(D) kcal-m/hr °C

Q2. Unit of thermal conductivity in S.I. units is
(A) J/m2 sec
(B) J/m °K sec
(C) W/m °K
(D) All of these

Q3. Thermal conductivity of solid metals with rise in temperature normally
(A) increases
(B) decreases
(C) remains constant
(D) may increase or decrease depending on temperature

Q4. Thermal conductivity of non-metallic amorphous solids with decrease in temperature
(A) increases
(B) decreases
(C) remains constant
(D) may increase or decrease depending on temperature

Q5. Heat transfer takes place as per –
(A) zeroth law of thermodynamics
(B) first law of thermodynamic
(C) second law of the thermodynamics
(D) Kirchoff’s law

Q6. 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
(A) conduction
(B) convection
(C) conduction and convection
(D) convection and radiation

Q7. 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
(A) conduction
(B) convection
(C) radiation
(D) conduction and convection

Q8. Sensible heat is the heat required to
(A) change vapour into liquid
(B) change liquid into vapour
(C) increase the temperature of a liquid of vapour
(D) convert water into steam and superheat it

Q9. The insulation ability of an insulator with the presence of moisture would
(A) increase
(B) decrease
(C) remain unaffected
(D) may increase/decrease depending on temperature and thickness of insulation

Q10. When heat is Transferred by molecular collision, it is referred to as heat transfer by
(A) conduction
(B) convection
(C) radiation
(D) convection and radiation.

Q11. Heat transfer in liquid and gases takes place by
(A) convection
(B) radiation
(C) conduction and convection
(D) convection and radiation

Q12. Which of the following is the case of heat transfer by radiation
(A) heating of building
(B) cooling of parts in furnace
(C) heat received by a person from fireplace
(D) All of these

Q13. Heat is closely related with
(A) fluids
(B) energy
(C) temperature
(D) entropy

Q14. Pick up the wrong case. Heat flowing from one side to other depends directly on
(A) surface area
(B) thickness
(C) temperature difference
(D) thermal conductivity

Q15. Metals are good conductors of heat because
(A) their atoms collide frequently
(B) their atoms-are relatively far apart
(C) they have high density
(D) All of these

Q16. Which of the following is a case of steady state heat transfer
(A) air preheaters
(B) heating of building in winter
(C) All of these
(D) None of these

Q17. Total heat is the heat required to
(A) change vapour into liquid
(B) change liquid into vapour
(C) increase the temperature of a liquid or vapour
(D) convert water into steam and superheat it

Q18. Cork is a good insulator because it has
(A) free electrons
(B) atoms colliding frequency
(C) low density
(D) porous body

Q19. Thermal conductivity of water in general with rise in temperature
(A) increases
(B) decreases
(C) remains constant
(D) may increase or decrease depending on temperature

Q20. Thermal conductivity of water at 20°C is of the order of
(A) 0.15
(B) 0.24
(C) 0.42
(D) 0.51