71.
Refrigeration is a process which

72.
Blowing Air with open pipe is an example of :

73.
Which of the following is not reversible?

74.
In a diesel engine the high temperature needed to ignite the fuel is achieved by

75.
Heat transfer horizontally within the atmosphere is called

76.
________ states that internal energy is a function of state and the increase in internal energy is equal to the sum of the heat supplied to system and work done by the system.

77.
Which phase change is an example of an exothermic process?

78.
The velocity of heat radiation in vacuum is

79.
In a Carnot engine when heat is taken from the source, its temperature

80.
Even after sunset, the air near the Earth's surface continue to receive heat due to