Back to Directory
NEET PHYSICSMedium

An ideal gas undergoes four different processes from the same initial state (figure). Four processes are adiabatic, isothermal, isobaric and isochoric. Out of 11, 22, 33 and 44, which one is adiabatic?

A

4

B

3

C

2

D

1

Step-by-Step Solution

  1. Identify the Processes by Slope: On a Pressure-Volume (P-V) diagram, thermodynamic processes can be identified by their characteristic slopes.
  2. Isobaric and Isochoric: An isobaric process occurs at constant pressure, represented by a horizontal line (slope = 00). An isochoric process occurs at constant volume, represented by a vertical line (slope = ∞\infty).
  3. Isothermal vs Adiabatic: For an isothermal process, PV=constantPV = \text{constant}, and its slope on the P-V curve is dPdV=−PV\frac{dP}{dV} = -\frac{P}{V}. For an adiabatic process, PVγ=constantPV^\gamma = \text{constant}, and its slope is dPdV=−γPV\frac{dP}{dV} = -\gamma \frac{P}{V}.
  4. Conclusion: Because the heat capacity ratio γ>1\gamma > 1, the magnitude of the slope of the adiabatic curve is greater than that of the isothermal curve. Therefore, the adiabatic curve is always steeper than the isothermal curve. In the standard visual representation of this problem, curve 22 is designated as the adiabatic process due to its relative steepness compared to the isothermal curve.
Practice Mode Available

Master this Topic on Sushrut

Join thousands of students and practice with AI-generated mock tests.

Get Started