Chapter 36 of 2363 min read

First law, work and internal energy

Why this is asked: Internal energy is a state function — for an ideal gas it depends on temperature alone — while heat and work are path-dependent, so two different processes between the same states can have very different Q and W despite identical ΔU.

This chapter is part of a paid pack

A sample of the book is free to read — the rest, including this chapter, unlocks with full access.

See pricing

Test yourself

•Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radius $r_{A}$ and $r_{B}$ , respectively. On supplying an equal amount of heat to both the systems reversibly under constant pressure, the pistons of gas A and B are displaced by 16 cm and 9 cm, respectively. If the change in their internal energy is the same, then the ratio $\frac{r _{A}}{r _{B}}$ is equal to:
•A thermodynamic system is taken through the cycle $ab c d a$ shown in the $P$ – $V$ diagram. The work done by the gas along the path $b c$ is:

Open this in the full syllabus view · Physics

ShareWhatsApp Telegram