The branch of science concerned with the ” nature and interaction ” of matter and energy.

Fig: Four Major Domains of Modern Physics
  1. Classical Physics

The physics that existed before the formulation of the theory of relativity and of quantum mechanics.

It explains matter and energy only on a scale familiar to human experience.

2. Quantum mechanics

The branch of physics relating to the very small.

Image by Gerd Altmann from Pixabay

It explains the behavior of:
matter and
– its interactions with energy
on the scale of atoms and subatomic particles

It describes how light and matter behaves at atomic stages.

In quantum mechanics, objects have probability of certain chance of being at point A, another chance of being at point B and so on.

3. Relativistic Mechanics

Science concerned with the motion of bodies whose relative velocities approach the speed of light c.