Thermodynamics ...

Assertion It is not possible for a system, unaided by an external agency to transfer heat from a body at lower temperature to another body at higher temperature.
Reason According to Clausius statement, \"No process is possible whose sole result is the transfer of heat from a cooled object to a hotter object.

Assertion If an electric fan be switched on in a closed room, the air of the room will be cooled.
Reason Fan air decreases the temperature of the room.

Assertion When a glass of hot milk is placed in a room and allowed to cool, its entropy decreases.
Reason Allowing hot object to cool does not violate the second law of thermodynamics.

Assertion In an adiabatic process, change in internal energy of a gas is equal to work done on or by the gas in the process.
Reason Temperature of gas remains constant in a adiabatic process.

Assertion The Carnot cycle is useful in understanding the performance of heat engines.
Reason The Carnot cycle provides a way of determining the maximum possible efficiency achievable with reservoirs of given temperatures.

Assertion Work done by a gas in isothermal expansion is more than the work done by the gas in the same expansion, adiabatically.
Reason Temperature remains constant in isothermal expansion and not in adiabatic expansion.

Assertion Zeroth law of thermodynamic explains the concept of energy.
Reason Energy is dependent on temperature.

Assertion Efficiency of a Carnot engine increased on reducing the temperature of sink.
Reason The efficiency of a Carnot engine is defined as ratio of net mechanical work done per cycle by the gas to the amount of heat energy absorbed per cycle from the source.

Assertion The entropy of the solids is the highest.
Reason Atoms of the solids are arranged in orderly manner

Assertion In an isolated system the entropy increases.
Reason The processes in an isolated system are adiabatic.