For an ideal gas at a temperature of $27^{\circ} \mathrm{C}$ and at constant pressure, the coefficient of volume expansion is nearly

Air is filled at $60^{\circ} \mathrm{C}$ in a vessel of open mouth. The vessel is heated to a temperature $f^{\circ} \mathrm{C}$ so that $1 / 4$ th of the air is escaped from the vessel. Assuming air as ideal gas and the volume of the vessel remaining constant, then the value of $t$ is

The temperature of 100 g of water is to be raised from $24^{\circ} \mathrm{C}$ to $90^{\circ} \mathrm{C}$ by adding steam at $100^{\circ} \mathrm{C}$ to it. The mass of the steam required in this process is (latent heat of steam is $540 \mathrm{cal} \mathrm{g}^{-1}$ )

Two identical containers $A$ and $B$ with frictionless pistons contain the same ideal gas at the same temperature and same volume $V$. The mass of the gas in $A$ is $m_A$ and that in $B$ is $m_B$. The gas in each cylinder is now allowed to expand isothermally to the same final volume $2 V$. The changes in the pressure of the gases in $A$ and $B$ are found to be $2 \Delta p$ and $3 \Delta p$ respectively. Then the relation between $m_A$ and $m_B$ is