JEE physics Assertion & Reason

(d) We can change the temperature of a body without giving (or taking) heat to (or from) it. For example in an adiabatic compression temperature rises and in an adiabatic expansion temperature false, although no heat is given or taken from the system in the respective changes.

(a) Entropy is a measure of the disorder or randomness of the system. Greater the randomness, greater the entropy.

(e) Zeroth law of thermodynamics explain the concept of temperature. According to which there exist a scalar quantity called temperature which is property of all thermodynamic system.

First law of thermodynamics is restatement of the principle of conservation of energy as applied to heat energy.

(c) First law of thermodynamics is restatement of the principal of conservation of energy as applied to heat energy.

(d) If an electric fan is switched on in a closed room, the air will be heated because due to motion of the fan, the speed of air molecules will increase. In fact, we feel cold due to evaporation of our sweat.

(a) Second law of thermodynamics can be explained with the help of example of refrigerator, as we know that refrigerator, the working substance extracts heat from colder body andrejects a large amount of heat to a hotter body with the help of an external agency i.e., theelectric supply of the refrigerator. No refrigerator can ever work without external supply of electric energy to it.

(d) When the door of refrigerator is kept open, heat rejected by the refrigerator to the room will be more than the heat taken by the refrigerator from the room (by an amount equal towork done by the compressor). Therefore, temperature of room will increase and so it will bewarmed gradually. As according to 2- law of thermodynamics, heat cannot be transferred on its own, from a body at lower temperature to another at higher temperature.

(a) Heat is similar to work in that both represent ways of transferring energy. Neither heat nor work is an intrinsic property of a system, that is, we cannot say that a system contains a certain amount of heat or work.

(d) We can change the temperature of a body without giving (or taking) heat to (or from) it. For example in an adiabatic compression temperature rises and in an adiabatic expansion temperature false, although no heat is given or taken from the system in the respective changes.