Question

The pressure exerted by a perfect gas is equal to

• A. mean kinetic energy per unit volume.
• B. half of mean kinetic energy per unit volume.
• C. two-thirds of mean kinetic energy.
• D. two-third of mean kinetic energy per unit volume.

Answer 1

The correct option is D two-third of mean kinetic energy per unit volume.

Mean kinetic energy is given by $U=C_{V}T=\frac{f}{2}RT=\frac{3}{2}RT$.

Since $P=\frac{nRT}{V}$

Thus $P=\frac{2}{3}\frac{U}{V}$

Hence, pressure is two-thirds of mean kinetic energy per unit volume.

Answer is option D.