The product of the pressure and volume of an ideal gas is

The adjoining figure shows graphs of pressure and volume of a gas at two temperatures $T_1$ and $T_2$. Which of the following is correct?

The equation of state for $n$ moles of an ideal gas is $PV = nRT$, where $R$ is a constant. The $SI$ unit for $R$ is

When the pressure of the gas contained in a closed vessel is increased by $2.5 \%$,the temperature of the gas increases by $4 \ K$. The initial temperature of the gas is (in $K$)

At constant temperature,increasing the pressure of a gas by $5\%$ will decrease its volume by ..... $\%$

An air bubble of volume $1.0 \; cm^{3}$ rises from the bottom of a lake $40 \; m$ deep at a temperature of $12 \; ^{\circ}C$. To what volume (in $cm^{3}$) does it grow when it reaches the surface,which is at a temperature of $35 \; ^{\circ}C$?