Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Total emissivity of polished silver compared to black body is
a. same
b. higher
c. more or less same
d. very much lower
e. very much higher.
Q. According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rateproportional to
a. absolute temperature
b. square of temperature
c. fourth power of absolute temperature
d. fourth power of temperature
e. cube of absolute temperatur
Q. Which of the following property of air does not increase with rise in temperature
a. thermal conductivity
b. thermal diffusivity
c. density
d. dynamic viscosity
e. kuiematic viscosity.
Q. The unit of Stefan Boltzmann constant is
a. watt/cm2 °K
b. watt/cm4 °K
c. watt2/cm °K4
d. watt/cm2 °K4
e. watt/cm2 °K2.
Q. In free con-vection heat transfer, Nusselt number is function of
a. Grashoff no. and Reynold no.
b. Grashoff no. and Prandtl no.
c. Prandtl no. and Reynold no.
d. Grashoff no., Prandtl no. and Reynold no.
e. none of the abov
Q. Stefan Boltzmann law is applicable for heat transfer by
a. conduction
b. convection
c. radiation
d. conduction and radiation combined
e. convection and radiation combined.
Q. The thermal diffusivities for gases are generally
a. more than those for liquids
b. less than those for liquids
c. more than those for solids
d. dependent on the viscosity
e. same as for the liquids.
Q. The thermal diffusivities for solids are generally
a. less than those for gases
b. jess than those for liquids
c. more than those for liquids and gases
d. more or less same as for liquids and gases
e. zerci.
Q. Thermal diffusivity of a substance is
a. directly proportional to thermal con¬ductivity
b. inversely proportional to density of substance
c. inversely proportional to specific heat
d. all of the above
e. none of the abov
Q. The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as
a. Krichoff’s law
b. Stefan’s law
c. Wien’ law
d. Planck’s law
e. Black body law.
Q. According to Stefan’s law, the total radiation from a black body per second perunit area is proportional to
a. absolute temperature
b. T2
c. T5
d. t
e. l/T.
Q. Tea pots are highly polished
a. So that they may not conduct heat from outside
b. So that they may absorb all radiation from outside
c. To make them attractive to look at
d. Because porcelain takes high polish
e. None of the above
Q. A shpere, a cube and a disc all of the same material, quality and volume are heated to 900K and left in air. Which of these will have the lowest rate of cooling
a. Sphere
b. All will have the same rate of cooling
c. Disc
d. Cube
e. 37,500 kg
Q. The overall co-efficient of heat transfer is expressed as
a. kcal/hr
b. kcal/m/hr
c. kcal/m2/hr/?C
d. None of the above
e. Nichrome