Branches of Physics - Learn all about various Physics Branches


Physics as a science which deals with the fundamental laws of nature. Physicist starts with observation and then try to formulate laws to explain various natural phenomena occurring around us. Physics is the foundation of various other sciences like Chemistry, Biology, etc.

This formulation of laws becomes very easy if these laws are expressed in mathematical forms. We can also say that mathematics is the language of physics. The roots of astronomy can be traced back to ancient civilizations like the Egyptians and the Indus valley civilization, but it became separate from philosophy when Galileo introduced experimental methods to test various theories. That is why he is also called the Father of Modern Physics.

Physics attempts to answer the questions such as

  • How does the universe begin?

  • What are the fundamental forces in nature?

  • What is the matter and what are its building blocks?

  • How does matter interact with each other?

  • How does physical quantities work behave on very small scales and very large scales.

Various branches of physics specifically deal with these questions. In the next sections, we will know about them one by one.

Classical Physics

The 16th and 17th centuries witnessed breakthroughs in Physics. New branches such as Thermodynamics, Optics, and electromagnetism evolved in this period. In this period Newton gave his laws of gravitation and published his famous work “Principia Mathematica”. This is known as the period of Classical Physics. Newton, Galileo, Kepler, Lagrange, Hamilton, and Jacobi are some famous physicists who worked in this field

Modern Physics

In 1900, Max Planck gave his theory of quanta and after 5 years comes the miraculous year in this history of physics. Albert Einstein published 5 papers in 1905, that shook the foundation of Physics. Most notable was the theory of relativity and the paper on Brownian motion. In the 1920s, the World witnessed the development of quantum mechanics. Some of these theories modified various principles of classical physics, Hence, 20th-century physics is also known as Modern Physics. Albert Einstein, Planck, Dirac, Schrodinger, Feynman, and Max born are some names who contributed to this field.

Nuclear Physics

Nuclear Physics is the study of nuclei and nucleons. Rutherford discovered the nucleus with his famous alpha particle experiment. In modern nuclear physics, we study the liquid drop model and the nuclear shell model. Nuclear fission and fusion are also studied in this field, which is a very essential process for advanced nuclear technologies like nuclear reactors. Alpha, Beta, and gamma decay can be understood using principles of nuclear physics. Radioactivity is an important part of nuclear processes. Chadwick, Rutherford, fermi, Marie curie, and fermi are some scientists who are famous in this field.

Atomic Physics

In nuclear physics, we study the nucleus but in atomic physics system of study is an atom, which has a nucleus as well as electrons. These days this field is also called AMO physics or atomic, molecular, and optical physics. Here we study electronic configurations, excitation, and deexcitation of energy levels in atoms. John Dalton was the first person to give the theory of atoms. Many physicists worked in this field, some notable names are - John Dalton, Niels Bohr, Thomson, Heisenberg, de Broglie, etc.

Mechanical properties of Solids and Fluids

Mechanical physics deals with mechanical properties of matters, such as stress, strain, elasticity, surface tension, viscosity, etc, Hooks’ law and young modulus are some familiar examples from this branch. Hooke, Torricelli, Archimedes, Stokes, and Bernoulli are some famous names who contributed to this branch.


Mechanics is a very fundamental branch of physics. It deals with the motion of a body and the cause of motion (Force). In this branch, we study kinematics newton’s law of motion, the law of gravitation, and the work-energy theorem. We also study the conservation of momentum and energy in this branch. Newton played a significant role in the development of this branch. Aristotle, Newton, Kepler, Lagrange, Euler, and cavendish are some physicists who contributed to this field.


Acoustics is a branch of physics that is concerned with the study of sound waves and behaviour in various mediums. We also study the production and transmission of sound in this branch. Here we also study the sound produced by different musical instruments and their effect on the human brain. Galileo, Colladon, Euler, Bernoulli, Sabine, etc. are famous physicists who worked in this area.


Optics is the branch that deals with the study of light and its properties. Here, we study various phenomena like reflection, refraction, diffraction, interference, etc. As we know light is an electromagnetic wave, hence the scope of this subject is very wide. Today many new subbranches are emerging in this field like -quantum optics, fibre optics, etc. Newton, Fermat, Rayleigh, Fresnel, and Young are some physicists who worked in this field.


The scope of thermodynamics is to study Heat, work, and various forms of energy. Temperature plays a significant role here. We can relate mechanical work to heat by the first law of thermodynamics. Second, the law of thermodynamics is a universal law, which means no valid physician law should violate this. Here We also study entropy and heat engines. Carnot, Maxwell, Kelvin, Boltzmann, Maxwell, etc. are some physicists who worked in this field.


Astrophysics is the study of the universe and its formation. It mainly deals with the physics of stars, galaxies, planets, etc. It uses thermodynamics, the theory of relativity, and chemistry also to study these objects. Kepler, Arthur Eddington, Fowler, Hawkin, and S. Chandrashekhar are some famous physicists who contributed to this field.


Physics is the study of nature and natural phenomena with scientific methods. Physicists try to formulate various physical laws to explain this phenomenon. Physics saw rapid progress in the 17th and 20th centuries, and classical and modern physics came into its present form, 20th-century physics known as Modern Physics. Physics is fundamental science but its application can be seen in engineering, medicine, and various cutting-edge technologies.


Q1. What are the four fundamental forces in Nature?

Ans. In Physics there are four fundamental forces.

  • Gravitational Force

  • Electromagnetic force

  • Strong nuclear force

  • Weak nuclear force

The strong nuclear force is the strongest and the gravitational force is the weakest force.

Q2. Which branch of physics has the most no. of Nobel Laureates?

Ans. Particle physics has most no. of Nobel laureates around 14%

Q3. State 2nd law of thermodynamics.

Ans. In terms of entropy, the Second law of thermodynamics says - Total entropy of a system never decreases, it either increases or remains constant.

Q4. Which branch of modern physics gives a framework to study objects at the atomic and subatomic levels.

Ans. Quantum mechanics gives the framework to study atomic and subatomic objects.

Q5. Which branch deals with the observational aspects of stars and galaxies?

Ans. Physical structure and properties of stars and galaxies are studied in astrophysics, however, the branch which deals with observation is called astronomy. It is one of the oldest branches of physics.

Updated on: 18-Apr-2023


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