Under constant temperature,the graph between $P$ and $1/V$ is:

Two identical glass bulbs are connected by a thin glass tube. The system is filled with gas at $0^{\circ}C$. If one bulb is placed in ice and the other in hot water,the pressure of the gas becomes $1.5$ times the initial pressure. What is the temperature of the hot water in $^{\circ}C$?

What is a mole? Write two equations for a mole.

The expansion of unit mass of a perfect gas at constant pressure is shown in the diagram. Here

Pressure of a gas of constant volume at $20^{\circ} C$ is $90 \ cm$ of $Hg$. At what temperature the pressure would change to $75 \ cm$ of $Hg$ (in $^{\circ} C$)?

$A$ tyre of a vehicle is filled with air having pressure $270 \text{ kPa}$ at $27^{\circ}C$. The air pressure in the tyre when the temperature increases to $37^{\circ}C$ is (in $\text{ kPa}$)