Question

A system is allowed to move from state A to B following path ACB by absorbing 80 J of heat energy. The work done by the system is 30 J. The work done by the system in reaching state B from A is 10 J through path ADB. Which statements are correct? (i) Increase in internal energy from state A tc state B is 50 J. (ii) If path ADB is followed to reach state B, $\Delta E=50J$ . (iii) If work done by the system in path AB is 20J,the heat absorbed during path AB = 70 J. (iv) The value $E_C-E_A$ is equal to $E_D-E_B$ . (v) Heat absorbed by the system to reach B from A through path ADD is 60 J.

• A. $\text{I,V}$
• B. $\text{I,III,V}$
• C. $\text{I, II, III, V}$
• D. $\text{I,IV,V}$

Answer 1

Answer: (C)

$ACB=AC+BC$ $ADB=AD+BD$ Heat absorbed $80J$ Work done by the system $=10J$ $\therefore$ $W=-10J$ $\therefore$ $W=-30$ Also $W=-10J$ $\therefore$ $E_B-E_A=50J$ $\therefore$ $Q=50+10=60J$