Question

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 + W

The first law of thermodynamics is the general law of conservation of energy applied to any system in which energy transfer from or to the surroundings (through heat and work) is taken into account. It states that the energy supplied to the system goes in partly to increase the internal energy of the system and the rest in work on the environment. Mathematically, ΔQ = ΔU + ΔW where ΔQ is the heat supplied to the system, ΔW is the work done by the system and ΔU is the change in internal energy of the system. ΔQ and ΔW depend on the path taken to go from initial to final states, but the combination ΔQ - ΔW is path independent.