Physics

'Physics' word is taken from Greek word 'Fusis'. Which means 'Nature'.
Physics is the branch of science in which we study about nature, natural principles, natural phenomenons.
Physics has two types -
(A) Classical physics - It is the knowledge of physics before 19th century.
It has following types -
1. Machines
(a) statics
(b) dynamic
(c) fluid motion
(d) aerodynamic
2. Electromagnetic
3. Thermodynamics
4. Wave motion
5. Optics etc.

(B) Modern physics - It is the knowledge of physics after 19th century.
In 1919 German scientist Max plank gave Quantum Theory.
According to quantum theory "light travel in the form of small packets of energy which know as quanta or photon". The rest mass of photon is zero so gravity doesn't apply to them.
On the basis of this theory so many changes are occurred in physics and that changes are called modern physics.
It has following types -
1. Solid state physics
2. Molecular physics
3. Atomic physics
4. Nuclear physics
5. Plasma physics
6. Quantum physics etc.