A balloon filled with helium ($32^{\circ} \mathrm{C}$ and 1.7 atm.) bursts. Immediately afterwards the expansion of helium can be considered as:

JEE Main · 2020 · 03 Sep 2020 · Shift 1 · Heat & Thermodynamics

A balloon filled with helium (

3 2^{\circ} C

and 1.7 atm.) bursts. Immediately afterwards the expansion of helium can be considered as:

(A)irreversible adiabatic
(B)reversible isothermal
(C)reversible adiabatic
(D)irreversible isothermal✓ Correct

Answer: (D)

Solution

When the balloon bursts the gas rushes out suddenly against the atmosphere, a change that cannot be traced through a succession of equilibrium states, so it is irreversible. Because the escaping helium is in immediate contact with the vast surrounding air, it quickly settles to the atmospheric temperature, so there is no net change of temperature and the expansion is treated as isothermal. The process is therefore irreversible and isothermal.

JEE Main · 2020 · 03 Sep 2020 · Shift 1 · Single correct option

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