# Physics

### Boyle law,Density,Thermal Expansion & Kinetic Theory

## What is the Boyle law

Pressure in a closed container changes if temperature changes,number of molecules +- and if volume changes.

Boyle’s Law deals with number 3; the relationship between volume and pressure when - the other two remain constant.According to Boyle’s Law, the amount a gas will compress is proportional to thepressure applied. Its mathematical expression is: P1V1=P2V2Where, P1 is the pressure of a quantity of gas with a volume of V1 and P2 is the pressure of the same quantity of gas when it has a volume of V2. This means that if nothing else changes, the volume of a given mass of gas is inversely proportional to pressure it is under. It is a linear relationship. If pressure on a gas doubles, its volume will decrease by 1/2. An alternative expression of the law is: PV = CThe product of the volume and pressure equals a constant.The relationship between pressure and volume results from the influence volume has on the rate at which gas molecules collide with the container walls. If the volume decreases, the molecules encounter the container walls more often. This is true even though the speed (temperature) of the individual molecules has not changed. An increased number of collisions equates to higher pressure. Conversely, if volume increases, the rate of collisions and the pressure decreases.