What is Physics? Notes
We are surrounded by physics all the time, and whether we realize it or not, we use physics every day.
Physics the study of matter and energy is an ancient and broad field of science.
The word ‘Physics’ comes from the Greek word ‘Fusis’ meaning ‘Knowledge of nature’ and in general, the field aims to analyze and understand the natural phenomena of the universe.
Though there are many definitions of physics, yet it can be defined as, “The study of the properties of matter, energy and their mutual relationship. ”
Scope and Expansion of Physics:
Physics is the branch of science, which deals with the properties of matter and energy and the relationship between them. It also tries to explain the material world and the natural phenomena of the – universe. The scope of physics is very wide and vast. It deals with not only the tiniest particle of atoms but it also dwells upon the natural phenomenon like galaxy, milky way, solar and lunar eclipse, etc.
Branches of Physics:
→ Branches of Physics
Physics is broadly classified into two parts.
(A) Classical physics
(B) Modern physics.
For your information
1. Macroscopic physics: Under macroscopic, physics comes the astronomical and earth-related incidents. The principles of classical mechanics clearly define macroscopic physics.
2. Microscopic physics: Microscopic physics covers the molecular, atomic and nuclear incidents. Quantum mechanics is studied to understand microscopic physics.
3. Mesoscopic physics: It is a subdiscipline of condensed matter physics that deals with materials of an intermediate length. The scale of these materials can be described as being between the size of a quantity of atoms (such as a molecule) and of materials measuring micrometers.
(A) Classical physics: Classical physics includes the traditional branches and topics that were recognized and fairly well developed before the beginning of the 20th century. It is mainly concerned with the laws of motion and gravitation by Sir Isaac Newton and a kinetic theory and thermodynamic by James Clark Maxwell. Classical physics is mainly concerned with matter and energy. In this branch, energy and matter are considered as separate entities.
Classical mechanics, Optics, Acoustics and Electromagnetics are the traditional branches of classical physics.
1. Mechanics: Mechanics is the study of physics of motion and how it relates to the applied forces. It lays the foundation of understanding the world around us through the question of how and why a thing moves.
2. Thermodynamics: Thermodynamics is the branch of physics, which deals with the study of heat and its relation with energy and work. This branch also deals with the study of gaseous systems. The change in temperature, internal energy and entropy of the system through external work are investigated. Modes of transfer of heat, efficiency of heat engines and refrigerators are also included in thermo¬-dynamics.
3. Electromagnetism: Electromagnetism is a branch of physics involving the study of electricity, magnetic effect and electromagnetic waves i. e., it deals with the study of electromagnetic force, a type of physical interaction that occurs between electrically charged particles. The electromagnetic force usually exhibits electromagnetic field such as the electric field, the magnetic field and light.
4. Acoustics: The word acoustics has been derived from a Greek word ‘akouen’, meaning ‘to hear’. Hence we can define acoustics as a branch of physics, which studies how sound is produced, transmitted, received and controlled. It also deals with the effects of sounds in various mediums t.e, gases, liquids and solids.
5. Optics: Optics involves the study of various phenomena connected with light and optical instruments like microscope, telescope etc. The topics studied in optics include images formed by lenses and mirrors, reflection, refraction, interference, diffraction, dispersion and polarization of light.
(B) Modern physics: Modern physics is the branch of physics, which is mainly concerned with the theory of relativity and quantum mechanics. Albert Einstein and Max Plank were the pioneers of modern physics.
- Relativity: Relativity is concerned with the study of those bodies that move with the speed almost the same as the speed of light.
- Quantum Mechanics: In quantum mechanics, we study about modern principles of physics, dual nature of light and particles etc.
- Atomic Physics: Atomic physics is the branch of physics which deals with the composition of atom apart from nucleus. It is mainly concerned with the arrangement and behaviour of electrons in shells around the nucleus.
- Nuclear Physics: Nuclear physics is the branch of physics which deals with constituents, structure, behaviour and interaction of atomic nuclei. In the modern age, nuclear physics has got a very wide scope. It is used in power generation, nuclear weapons, medicines etc.
Apart from these branches, there are many branches of physics. Some of them are… Bio Physics, Electronics, Plasma-Physics, High Energy Physics, Astrophysics, Condensed Matter Physics, Solid State Physics, Environmental Physics, Computational Physics, Polymer Physics, Materials Physics and Cryogenics.