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151.

The refrigerant used for the air-conditioning of passenger aircraft cabin is

A.	Ammonia	B.	Freon 11
C.	Freon 12	D.	Carbondioxide
E.	Air

152.

In vapour absorption system the function of rectifier is

A.	To cool the vapour leaving the analyzer	B.	To separate ammonia and water
C.	To dissolve ammonia in water	D.	To add energy from external source
E.	None of the above

153.

Two thermometers are constructed in the same way except that one has a spherical bulb and the other an elongated cylindrical bulb. Which one will respond quickly to temperature change?

A.	Spherical bulb thermometer	B.	Cylindrical bulb thermometer
C.	Both will respond in identical manner	D.	Cannot be ascertained on the basis of information provided

154.

"The difference between the length of a certain brass rod and that of a steel rod is clamped to be constant at all temperatures". The above statement

A.	can never be true	B.	can be valid only for temperatures below 0?C
C.	can be true provided their lengths are directly proportional to the linear coefficients of the material of the rod	D.	can be true provided their lengths are directly proportional to the linear coefficients of the material of the rod

155.

Hydrogen cannot be liquefied at room temperature by the application of pressure, because

A.	It has low density	B.	It has high viscosity
C.	Its thermal conductivity is high	D.	It is a diatomic molecule
E.	Its critical temperature is lower than the normal room temperature

156.

A refrigerating machine working on Reversed Carnot cycle takes out 2 kW per minute of heat from the system while working between temperature limits of 300?K and 200?K. The C.O.P. and power consumed by the cycle will be

A.	1,1 kW	B.	1, 2 kW
C.	2. 1 kW	D.	2, 2 kW
E.	0, 0 kW

157.

The COP of a reversed Carnot cycle is 5. The ratio of highest absolute temperature to the lowest absolute temperature

A.	5	B.	1.25
C.	1.2	D.	0.8
E.	0.2

158.

Which of the following refrigerant has the lowest specific volume?

A.	Freon 12	B.	Freon 22
C.	Carbondioxide	D.	Ammonia
E.	All the refrigerants have identical specific volume

159.

Which of the following has lowest COP?

A.	Vapour absorption cycle	B.	Vapour compression cycle using wet compression
C.	Vapour compression cycle using dry compression	D.	Vapour compression cycle with superheated vapour at the end of compression

160.

When the lower temperature is fixed, the COP of a refrigerating machine can be improved by

A.	Operating the machine at higher speeds
C.	Raising the higher temperature	D.	Lowering the higher temperature
E.	None of the above