Thermodynamics

JEE Main level, single correct, medium

99 of 190

Question 99 of 190

Consider two containers AA and BB containing monoatomic gases at the same Pressure (P)\left(P\right), Volume (V)\left(V\right) and Temperature (T)\left(T\right). The gas in AA is compressed isothermally to 18\dfrac{1}{8} of its original volume while the gas in BB is compressed adiabatically to 18\dfrac{1}{8} of its original volume. The ratio of final pressure of gas in BB to that of gas in AA is

Show answer and solution

Answer: (B) 44

In an isothermal process the temperature is constant.
PV=nRTPV=nRT
So, it can be written that

PV=PA(V8)⇒PA=8PPV={P}_{A}\left(\dfrac{V}{8}\right) \Rightarrow {P}_{A}=8P
In an adiabatic process,

PVγ=P{V}^{\gamma }=constant
γ\gamma for monoatomic gas is 53\dfrac{5}{3}
So, it can be written

PBP=(VV8)53⇒PB=32P\dfrac{{P}_{B}}{P}={\left(\dfrac{V}{\dfrac{V}{8}}\right)}^{\dfrac{5}{3}} \Rightarrow {P}_{B}=32P
Thus, the ratio of the pressures is

PBPA=32P8P=4\dfrac{{P}_{B}}{{P}_{A}}=\dfrac{32P}{8P}=4

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.

More Physics practice

JEE Main Physics practice question on Thermodynamics (Thermodynamic Processes), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.