The temperature of an ideal gas is increased from 100 K to 400 K . If ' $x$ ' is the root mean square velocity of its molecules at 100 K , r.m.s. velocity becomes

According to the kinetic theory of gases, when two molecules of a gas collide with each other then

During the isothermal expansion, a confined ideal gas does $(-150) \mathrm{J}$ of work against its surroundings. This means that

A body cools from $80^{\circ} \mathrm{C}$ to $50^{\circ} \mathrm{C}$ in 5 min . In the next time of ' t ' in, the body continues to cool from $50^{\circ} \mathrm{C}$ to $30^{\circ} \mathrm{C}$. The total time taken by the body to cool from $80^{\circ} \mathrm{C}$ to $30^{\circ} \mathrm{C}$ is [The temperature of the surroundings is $20^{\circ} \mathrm{C}$.]