Scope of Physics

Table of Contents

• Scope of Physics
• Branches of physics
• Main sub-disciplines in physics:
  • 1. Mechanics:
  • 2. Optics:
  • 3. Thermodynamics:
  • 4. Electrodynamics:
  • 5. Quantum mechanics:
  • 6. Relativity:

Scope of Physics

The scope of physics is very wide. Every event, which occurs around us in our daily life, is governed by one or the other principle of physics.

One way of getting the idea of the scope of physics is to look at its various sub-disciplines. Another way is look at the vast range of magnitude of the physical quantities it deals with.

Branches of physics

Physics has two main domains of study—macroscopic and microscopic. Classical physics deals with macroscopic phenomena which may be at the laboratory, terrestrial and astronomical scales. It includes branches like mechanics, optics, thermo­dynamics and electrodynamics. Quantum mechanics deals with microscopic phenomena at the minute scales of atoms, molecules and nuclei.

Main sub-disciplines in physics:

1. Mechanics:

It deals with the equilibrium or motion of material bodies at low speeds. It is based on laws of gravitation. The propulsion of rocket, equilibrium of rod bent under a load, propagation of water waves or sound waves in air, etc., are studied in mechanics.

2. Optics:

It deals with the nature and propagation of light. It deals with the formation of images by mirrors and lenses, colours in thin films, etc.

3. Thermodynamics:

It deals with a macroscopic system in equilibrium and is concerned with the changes in internal energy, temperature, entropy, etc., of the system through external work and heat. Here we study the efficiency of heat engines and refrigerators.

4. Electrodynamics:

It deals with electric and magnetic phenomena associated with charged and magnetic bodies. It is based on laws given by Coulomb, Oersted, Ampere and Faraday, which were later on unified by Maxwell. It deals with problems like motion of current-carrying conductor in a magnetic field, propagation of radiowaves through the atmosphere, etc.

5. Quantum mechanics:

It deals with the mechanical behaviour of sub-microscopic particles like atoms and nuclei and their interaction with projectiles like electrons, photons and other elementary particles.

6. Relativity:

It is theory of invariance in nature. It deals with the motion of the particles having speeds comparable to the speed of light.

An exciting field of research these days is a new domain, called mesoscopic physics, which is intermediate between the microscopic and macroscopic domains and deals with a few tens or hundreds of atoms.

The scope of physics is truly vast. We can see in another way that the scope of physics is truly vast. It covers wide ranges of mass, length, time, energy, etc. The mass of an object can vary from 10^-30 kg (mass of an electron) to 10⁵⁵kg (mass of the universe). The length of an object can vary from 10^-14m (size of a nucleus) to 10²⁶m (size of the universe). Time interval can vary from 10^-22s (time taken by light to cross a nuclear distance) to 10¹⁸s (life of the sun). The everyday phenomena lie in the middle ranges.