Q.1

When α is absorptivity, ρ is reflectivity and τ is transmittivity, then for a diathermanous body,

  • α = 1, ρ = 0 and τ = 0
  • α = 0, ρ = 1 and τ = 0
  • α = 0, ρ = 0 and τ = 1
  • α + ρ = 1 and τ = 0
Q.2

Which of the following statement is wrong?

  • The value of C.O.P. is always greater than one.
  • In a vapour compression system, the condition of refrigerant before entering the compressor is dry saturated vapour.
  • The space between the saturated liquid line and saturated vapour line, in a pressure enthalpy chart, is wet vapour region.
  • none of the above
Q.3

The coefficient of performance of a domestic refrigerator is __________ as compared to a domestic air-conditioner.

  • same
  • less
  • more
Q.4

The refrigerant used for absorption refrigerators working on heat from solar collectors is a mixture of water and

  • carbon dioxide
  • sulphur dioxide
  • lithium bromide
  • R-12
Q.5

Thermal conductivity of solid metals __________ with rise in temperature.

  • remains same
  • decreases
  • increases
Q.6

In a shell and tube heat exchanger, baffles are provided on the shell side to

  • improve heat transfer
  • provide support for tubes
  • prevent stagnation of shell side fluid
  • all of these
Q.7

During sensible cooling of air, specific humidity

  • remains constant
  • increases
  • decreases
Q.8

The coefficient of performance of vapour compression refrigeration system is quite __________ as compared to air refrigeration system.

  • low
  • high
Q.9

The undesireable property of a refrigerant is

  • non-toxic
  • non-flammable
  • non-explosive
  • high boiling point
Q.10

The refrigerant used for absorption refrigerators working on heat from solar collectors is a mixture of water and

  • carbon dioxide
  • sulphur dioxide
  • lithium bromide
  • R-12
Q.11

The coefficient of performance (C.O.P.) is the reciprocal of the efficiency of a heat engine.

  • True
  • False
Q.12

The coefficient of performance (C.O.P.) is the reciprocal of the efficiency of a heat engine.

  • True
  • False
Q.13

When there is an addition of water vapour to the air of enclosed space, a gain in __________ is said to occur.

  • sensible heat
  • latent heat
Q.14

During humidification process, dry bulb temperature

  • remains constant
  • increases
  • decreases
Q.15

The process of heat transfer from one particle of the body to another is called conduction, when the particles of the body

  • move actually
  • do not move actually
  • affect the intervening medium
  • does not affect the intervening medium
Q.16

In a black body, all radiations are rejected.

  • True
  • False
Q.17

The horizontal and non-uniformly spaced lines on a psychrometric chart indicates

  • dry bulb temperature
  • wet bulb temperature
  • dew point temperature
  • specific humidity
Q.18

The average value of thermal conductivity for water atC saturate is about 0.51.

  • True
  • False
Q.19

The transfer of heat by molecular collision is known as

  • conduction
  • convection
  • radiation
  • none of these
Q.20

In order to collect liquid refrigerant and to prevent it from going to a __________ , a device known as accumulator is used at the suction of compressor.

  • compressor
  • condenser
  • expansion valve
  • evaporator
Q.21

Stefan-Boltzmann law is applicable for heat transfer by convection.

  • Agree
  • Disagree
Q.22

Oil separator in a refrigeration cycle is installed

  • before compressor
  • between compressor and condenser
  • between condenser and evaporator
  • between condenser and expansion valve
Q.23

The dry bulb temperature during sensible heating of air

  • remains constant
  • increases
  • decreases
Q.24

The wet bulb temperature atrelative humidity is __________ dry bulb temperature.

  • same as
  • lower than
  • higher than
Q.25

Stefan-Boltzmann law is applicable for heat transfer by convection.

  • Agree
  • Disagree
Q.26

Wein's law states that the wave length corresponding to __________ is proportional to the absolute temperature.

  • minimum energy
  • maximum energy
Q.27

The dehumidification process, on the psychrometric chart, is shown by

  • horizontal Sine
  • vertical line
  • inclined line
  • curved line
Q.28

The relative humidity __________ as air gets drier.

  • increases
  • decreases
Q.29

Fourier's law of heat conduction gives the heat flow for

  • irregular surfaces
  • non-uniform temperature surfaces
  • one dimensional cases only
  • two dimensional cases only
Q.30

Wein's law states that the wave length corresponding to __________ is proportional to the absolute temperature.

  • minimum energy
  • maximum energy
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