KNOW PHYSICS

 Heat Engine Any practical machine which converts heat into mechanical work is called a heat engine. Heat engines in their operation absorbs heat at Higher temperature, convert part of it into mechanical work, and reject the remaining heat at a low temperature. In this process, a workin substance is used. In steam engines, the working substance is water vapour, and in all gas engines the working substance is a combustible mixture of gases. The working substance goes through some processes that involes change of pressure(P), Volume(V) and temperature, and then returns to the initial state. This is called as one cycle of operation, since it is a cyclic process. Heat engines were from long time but were only  made useful at the time of industrial revolution in 18th century. Carnot's Ideal Heat Engine  French engineer  Sadi Carnot  conceived a theoretical engine in 1824. The engine is not practically possible. It has maximum efficiency. It is an ideal heat engine. It has following par