Question

A one mole of an ideal gas expands adiabatically at constant pressure such that its temperature T The value of the adiabatic constant of gas is

• A. 1.3
• B. 1.5
• C. 1.67
• D. 2.0

Answer 1

Answer: (B)

1.5

Answer 2

: In an adiabatic expansion.

$P V \gamma =$constant

$\because P = \frac { R T } { V }$ (for 1 mole of gas)

$\therefore \left( \frac { R T } { V } \right) V ^ { \gamma } =$constant

As $T \propto \frac { 1 } { \sqrt { V } } \therefore 1 - \gamma = - \frac { 1 } { 2 }$ $\gamma = 1 + \frac { 1 } { 2 } = \frac { 3 } { 2 } = 1.5$