Practice portal › Thermodynamics › First Law and Molar Specific Heats

A gas can be taken from A to B via two different processes, ACB and ADB. When the path ACB is used, 60 J of heat flows into the system and 30 J of work is done by the system. If the path ADB is used, the work done by the system is 10 J. The heat flow into the system along the path ADB is

Asked in JEE Main 9th Jan 1st Shift 2019 · First Law and Sign Convention

Figure: First Law and Sign Convention
Answer: (3) 40 J

Step-by-step solution

Internal energy is a state function, so Δ U is the same on both paths.

Along ACB: Δ U=Q-W=60-30=30 J.

Along ADB: Q=Δ U+W=30+10=40 J.

Why the other options are wrong

More First Law and Molar Specific Heats questionsAll First Law and Molar Specific Heats questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer