Thermodynamics ...

Assertion Air quickly leaking out of a balloon becomes cooler.
Reason The leaking air undergoes adiabatic expansion.

Assertion Thermodynamic processes in nature are irreversible.
Reason Dissipative effects can not be eliminated.

Assertion When a bottle of cold carbonated drink is opened, a slight fog forms around the opening.
Reason Adiabatic expansion of the gas causes lowering of temperature and condensation of water vapours.

Assertion The isothermal curves intersect each other at a certain point.
Reason The isothermal change takes place slowly, so the isothermal curves have very little slope.

Assertion In adiabatic compression, the internal energy and temperature of the system get decreased.
Reason The adiabatic compression is a slow process.

Assertion In isothermal process whole of the heat energy supplied to the body is converted into internal energy.
Reason According to the first law of thermodynamics ΔQ = ΔU + PΔV.

Assertion We can not change the temperature of a body without giving (or taking) heat to (or from) it.
Reason According to principle of conservation of energy, total energy of a system should remain conserved.

Assertion The specific heat of a gas in an adiabatic process is zero and in an isothermal process is infinite.
Reason Specific heat of a gas is directly proportional to change of heat in system and inversely proportional to change in temperature.

Assertion The heat supplied to a system is always equal to the increase in its internal energy.
Reason When a system changes from one thermal equilibrium to another, some heat is absorbed by it.

Assertion The temperature of the surface of the sun is approximately 6000 K. If we take a big lens and focus the sun rays, we can produce a temperature of 8000 K.
Reason This highest temperature can be produced according to second law of thermodynamics.