### Pressure Law

Pressure law states that for a fixed mass of gas, the pressure of the gas is directly proportional to the absolute temperature of the gas provided the volume of the gas is kept constant.

$$\begin{array}{l}P\alpha T\\ P=kT\\ \frac{P}{T}=k\end{array}$$

$$\begin{array}{l}P\alpha T\\ P=kT\\ \frac{P}{T}=k\end{array}$$

#### Formula:

$$\frac{{P}_{1}}{{T}_{1}}=\frac{{P}_{2}}{{T}_{2}}$$#### Explanation

- The kinetic energy of gas molecules increases with temperature.
- The air molecules collide with the wall of the container at higher velocity and frequency.
- The pressure in the gas increases, causing an increase in volume.

#### Graph

- In the graphs above, the first graph shows that P is directly proportional to the absolute temperature.
- The second graph shows that, if the temperature is in °C, the graph does not pass through the origin.
- The third and the forth graphs shows that P/T is always constant for all value of P and T.