## What is rigid body?

A system of large number of particles in which the distance between any two particles remains fix throughout the motion is called rigid body.

## What is the ideal gas equation?

The equation of state of an ideal gas is given by,

PV = nRT

Where, n is the number of moles of the gas and R is the gas constant for one mole of the gas.

### The gas law

#### Boyle’s law

If $$\mu$$ and T are constant then idael gas equation becomes, $$PV = Constant$$ or $$P \propto \frac{1}{V}$$ This is the Boyle’s law.

#### Charle’s law

If $$\mu$$ and P are constant then idael gas equation becomes,
$$V \propto T$$ This is the Charle’s law.

#### Gay lussac’s law

If $$\mu$$ and V are constant then idael gas equation becomes,
$$P \propto T$$

This is the Gay lussac’s law.

## What are the different types of waves?

Basically waves can be three types:

1. Mechanical waves
2. Electromagnetic waves
3. Matter waves

### Mechanical waves

Waves which can be produced and propagated only in a material medium are known as mechanical waves.
Water waves, sound waves, waves on string, seismic waves etc. are the example of mechanical waves.
The propagation of mechanical wave depends on the elasticity and inertia of the medium. Thus, these waves are known as elastic waves.

Mechanical waves are two types: Transverse waves and longitudinal waves.

#### Transverse waves

Waves on the water surface, light waves, wave generated on the string etc are the examples of transverse waves.

#### Longitudinal wave

Sound wave propagated in air is the example of longitudinal waves.

### Electromagnetic waves

Those waves which requires no material medium for their production and propagation, this means it propagates in vacuum. Such waves are called electromagnetic waves.
Visible light, ultraviolet light, radio waves, microwaves, X-rays etc are the examples of electromagnetic waves.

### Matter waves

These waves are associated with moving particles of matter like electrons, protons, neutrons, atoms, molecules etc.