Answer:
Kelvin-Plank statement of the second law:
" It is not possible to construct a heat engine which operates cyclically which in effect absorbs energy from a thermal reservoir (single) in the form of heat and deliver in output an equivalent or net work work"
Simplified form:
It is impossible to device a heat engine with 100% thermal efficiency i.e, it cannot transfer heat from a thermal reservoir to net work done i.e, some amount of heat will be lost.
Clausius Statement of the second law:
" It is impossible to design a device in a way that when operating in a cycle , it will transfer heat from a cooler body to a hotter body only without any other effect"
Simplified form:
It is not possible to design a device which can transfer heat from low to high temperatures without the requirement of any external work as input. With the help of external work, heat, in the system can be transferred from low to high temperatures.