Question

A cylinder of capacity 20 litres is filled with $H_{2}$ gas. The total average kinetic energy of translatory motion of its molecules is $1.5 \times 10^{5}J$. The pressure of hydrogen in the cylinder is

• A. $2 \times 10^{6}N/m^{2}$
• B. $3 \times 10^{6}N/m^{2}$
• C. $4 \times 10^{6}N/m^{2}$
• D. $5 \times 10^{6}N/m^{2}$

Answer 1

Answer: (D)

$5 \times 10^{6}N/m^{2}$

Answer 2

Kinetic energy E = $1.5 \times 10^{5}J$, volume V = 20 litre

= $20 \times 10^{- 3}m^{3}$

Pressure $= \frac{2}{3}\frac{E}{V} = \frac{2}{3}\left( \frac{1.5 \times 10^{5}}{20 \times 10^{- 3}} \right) = 5 \times 10^{6}N ⥂ / ⥂ m^{2}$.