Pressure is defined as the force acting per unit area.

Formula for Pressure

SI unit: Pascal (P) or Nm-2

Pressure In Liquids:

Pressure in liquids is given by the formula:

Pressure = density × gravity × height

Density Pressure in Water

Pressure increases with the depth and density of the liquid.

While calculating pressure in liquids height should be always measured from the bottom.

Pressure In Gases:

Pressure in gases is due to the bombardment of molecules on walls of container and it can be measured by manometers.


It is an instrument for measuring atmospheric pressure. There are two types of barometers mercury barometer and water barometer

Boyle’s  Law:

Boyle’s law states that the pressure exerted by gas is inversely proportional to the volume provided the temperature remains constant.


Boyle's Law

P1v1 = p2v2

Whenever temperature increases the volume increases

Boyle's Law with Temperature

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  1. more notes and easy access to question patterns would b appreciated

  2. really helped in my igcse paper thanks a bunch!!!

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