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

279) The ultimate analysis of coal consists of the determination of the percentage of

280) The change of entropy, when heat is removed from the gas, is positive.

281) The ratio of root mean square velocity to average velocity of gas molecules at a particular temperature is