MCQ
2181. During a refrigeration cycle heat is rejected by the refrigerant in a-
compressor
condenser
evaporator
expansion valve
2182. Which of the following refrigerant is highly toxic and flammable?
sulphur dioxide
Freon-12
Ammonia
Carbon dioxide
2183. According to Kelvin-Planck statement, it is impossible to construct a device operating on a cycle which transfers heat from-
Low pressure heat reservoir to high pressure reservoir
Low temperature heat reservoir to high temperature reservoir
High pressure heat reservoir to low pressure reservoir
High temperature heat reservoir to low temperature reservoir
2184. A condenser of refrigeration system rejects heat at the rate of 120kW while its compressor consunes a power of 30 kW. The coefficient of performance of the system would be-
1/4
3
4
1/3
2185. In an isothermal process-
There is no change in enthalpy
There is no change in internal energy
There is no change in temperature
All of these
2186. Measurement of temperaturę is based on-
Thermodynamic properties
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
2187. Kelvin-Planck's law deals with-
Conservation of heat
Conservation of work
Conversion of heat into work
Conversion fo work into heat
2188. Temperature of a gas is produced due to-
Its heating value
Kinetic energy of molecules
Repulsion of molecules
Attraction of molecules
2189. According to kinetic theory of gases, the absolute zero temperature is attained when-
Volume of the gas is zero
Pressure of the gas is zero
Kinetic energy of the molecules is zero
Specific heat of gas is zero
2190. A good refrigerant should have-
high latent heat of vaporisation and low freezing point
high operating pressures and low freezing point
high specific volume and high latent heat of vaporisation
low COP and low freezing point
2191. A domestic refrigerator has the co- efficient of performance-.
equal to 10
less than 10
more than 10
none
2192. A refrigerant with the highest critical pressure is-
R-11
R-22
R-12
Ammonia
2193. The capacity of a domestic refrigerator is the range of-
0.1 to 0.3 TR
1 to 3 TR
3 to 5 TR
5 to 7 TR
2194. Superheated vapour behaves—
Exactly as gas
As steam
As ordinary vapour
Approximately as a gas
2195. Zeroth law of thermodynamics-
Deals with conversion of mass and energy
Deals with reversibility and irreversibility of process
States that if two systems are both in equilibrium with a third system, they are in thermal equilibrium with each other
Deals with heat engines
2196. The temperature of ammonia after compression in a vapour compression system is-
20 to 50°C
70 to 100°C
50 to 70°C
none of these
2197. Intensive property of a system is one whose value-
Depends on the mass of the system, like volume
Does not depend on the mass of the system, like temperature, pressure etc.
Is not dependent on the path followed but on the state
Is dependent on the path followed and not on the state
2198. A standard ice point temperature corresponds to the temperature of-.
water at 0°C
ice at-4°C
solid and dry ice
mixture of ice and water under equilibrium conditions
2199. Which of the following refrigerant has the lowest freezing point?
R-11
R-22
R-12
Ammoma
2200. Which of the following variables controls the physical properties of a perfect gas?
Pressure
Temperature
Volume
All of the above