Q.1

The heat transfer takes place according to

  • Zeroth law of thermodynamics
  • First law of thermodynamics
  • Second law of thermodynamics
  • Kirchhoff's law
Q.2

In case of solids, the heat transfer takes place according to radiation.

  • Correct
  • Incorrect
Q.3

A perfect black body is one which

  • is black in colour
  • absorbs heat radiations of all wave lengths falling on it
  • reflects all the heat radiations
  • transmits the heat radiations
Q.4

The by-pass factor for a cooling coil

  • increases with increase in velocity of air passing through it
  • decreases with increase in velocity of air passing through it
  • remains unchanged with increase in velocity of air passing through it
  • may increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering
Q.5

The subcooling in a refrigeration cycle

  • does not alter C.O.P.
  • increases C.O.P.
  • decreases C.O.P.
  • none of these
Q.6

An electrolux refrigerator is called a __________ absorption system.

  • single fluid
  • two fluids
  • three fluids
Q.7

A water cooled condenser operates at a __________ condensing temperature than an air-cooled condenser.

  • higher
  • lower
Q.8

Degree of saturation or percentage humidity is

  • the mass of water vapour present in 1 m3 of dry air
  • the mass of water vapour present in 1 kg of dry air
  • the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
  • the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
Q.9

The difference between dry bulb temperature and wet bulb temperature, is called

  • dry bulb depression
  • wet bulb depression
  • dew point depression
  • degree of saturation
Q.10

The heat transfer by radiation __________ a medium.

  • requires
  • does not require
Q.11

The relative humidity decreases as air gets wet.

  • True
  • False
Q.12

The coefficient of performance of Heat Pump is always __________ one.

  • equal to
  • less than
  • greater than
Q.13

Defrosting of a refrigerator may be done by stopping the compressor for a short period.

  • Correct
  • Incorrect
Q.14

During sensible cooling of air __________ decreases.

  • wet bulb temperature
  • relative humidity
  • dry bulb temperature
  • specific humidity
Q.15

Thermal conductivity of water __________ with rise in temperature.

  • remains same
  • decreases
  • increases
  • may increase or decrease depending upon temperature
Q.16

The temperature of ammonia after compression in a vapour compression system is

  • 20 to 50° C
  • 50 to 70° C
  • 70 to 110° C
  • none of these
Q.17

During sensible cooling of air __________ decreases.

  • wet bulb temperature
  • relative humidity
  • dry bulb temperature
  • specific humidity
Q.18

The wet bulb temperature lines, on the psychrometric chart, are curved lines.

  • True
  • False
Q.19

In aqua-ammonia and Lithium-bromide water absorption refrigeration systems, the refrigerants are respectively

  • water and water
  • water and lithium bromide
  • ammonia and lithium bromide
  • ammonia and water
Q.20

According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)

  • Pb = pa - pv
  • Pb = pa + pv
  • Pb = pa x pv
  • Pb = pa/pv
Q.21

Thermal diffusivity is a

  • function of temperature
  • physical property of a substance
  • dimensionless parameter
  • all of these
Q.22

As relative humidity decreases, the dew point temperature will be __________ wet bulb temperature.

  • same as
  • lower than
  • higher man
Q.23

Thermal diffusivity is a

  • function of temperature
  • physical property of a substance
  • dimensionless parameter
  • all of these
Q.24

In a psychrometric process, the sensible heat added iskJ/s and the latent heat added iskJ/s. The sensible heat factor for the process will be

  • 0.3
  • 0.6
  • 0.67
  • 1.5
Q.25

In a psychrometric process, the sensible heat added iskJ/s and the latent heat added iskJ/s. The sensible heat factor for the process will be

  • 0.3
  • 0.6
  • 0.67
  • 1.5
Q.26

The condition of refrigerant after leaving the compressor and before entering the condenser is superheated vapour.

  • Yes
  • No
Q.27

The process of heat transfer from a hot body to a cold body, in a straight line, without affecting the intervening medium, is called radiation.

  • True
  • False
Q.28

The amount of radiation mainly depends upon the

  • nature of the body
  • temperature of the body
  • type of surface of the body
  • all of these
Q.29

The relative humidity is defined as

  • the mass of water vapour present in 1 m3 of dry air
  • the mass of water vapour present in 1 kg of dry air
  • the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
  • the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
Q.30

The relative humidity is defined as

  • the mass of water vapour present in 1 m3 of dry air
  • the mass of water vapour present in 1 kg of dry air
  • the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
  • the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
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