Heat Transfer MCQs | Heat Transfer Multiple Choice Questions with Answers

61 Total emissivity of polished silver compared to black body is
[A] Same
[B] Higher
[C] More Or Less Same
[D] Very Much Lower
Answer: Very Much Lower
62 Stefan Boltzmann law is applicable for heat transfer by
[A] conduction
[B] convection
[C] radiation
[D] conduction and radiation combined
Answer: radiation

DOWNLOAD CURRENT AFFAIRS PDF FROM APP

63 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
Answer: more than those for liquids and gases
64 According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to
[A] absolute temperature
[B] T2
[C] T5
[D] t
Answer: t
65 The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit
[A] Temperature
[B] Thickness
[C] Area
[D] Time
Answer: Time
66 The ratio of the energy absorbed by the body to total energy falling on it is called
[A] Absorptive Power
[B] Emissive Power
[C] Absorptivity
[D] Emissivity
Answer: Absorptive Power
67 The amount of radiation mainly depends on
[A] nature of body
[B] temperature of body
[C] type of surface of body
[D] All Of The Above
Answer: All Of The Above
68 The emissive power of a body depends upon its
[A] Temperature
[B] Wave Length
[C] Physical Nature
[D] All Of The Above
Answer: All Of The Above
69 In regenerator type heat exchanger, heat transfer takes place by
[A] direct mixing of hot and cold fluids
[B] a complete separation between hot and cold fluids
[C] flow of hot and cold fluids alternately over a surface
[D] generation of heat again and again
Answer: flow of hot and cold fluids alternately over a surface
70 If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of
[A] 3
[B] 6
[C] 9
[D] 81
Answer: 81