There are many branches in Physics. But some branches are main they are
1. Energy 2. Electricity 3. Magnetism 4. Force 5. Light 6. Sound
7. Gravity 8. Mechanics 9. Thermodynamics 10. Optics.
Energy is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.
All forms of energy are associated with motion. Any given body has kinetic energy if it is in motion.
A tensioned device such as a bow or spring, though at rest, has the potential for creating motion; it contains potential energy because of its configuration.
Similarly, nuclear energy is potential energy because it results from the configuration of subatomic particles in the nucleus of an atom.
The most commonly seen forms of energy that you find around yourself are:
Energy can be converted from one form to another in various ways. Usable mechanical or electrical energy is, for instance, produced by many kinds of devices, including fuel-burning heat engines, generators, batteries, fuel cells etc.
Electricity has changed the living standards of human beings. We cannot imagine a life without electricity. Almost all of our gadgets run on electricity or the power provided by the batteries. Some of the uses of electricity that you see in your everyday life can be:
Electricity has to be created. It can be done at a hydro-electric power plant. Such plants are usually built on dams built on rivers where water flows with maximum pressure.
Electric power has had an impact on modern agriculture that has been at least as significant as that of either steam or gasoline, because electricity in its nature is far more versatile than the earlier power sources.
Magnetism is a phenomenon associated with the motion of electric charges. This motion can take many forms. It can be an electric current in a conductor or charged particles moving through space, or it can be the motion of an electron in atomic orbit. Magnetism is also associated with elementary particles, such as the electron, that have a property called spin.