274) The __________ states that change of internal energy of a perfect gas is directly proportional to the change of temperature.

275) A closed cycle gas turbine works on Joule's cycle.

276) The workdone in a free expansion process is zero.

277) When a system changes its state from one equilibrium state to another equilibrium state, then the path of successive states through which the system has passed, is known as

278) The fuel mostly used in blast furnace for extracting pig iron from iron ores is