

What Are the Main Principles and Branches of Basic Physics?
Basic Definition of Physics
Basically, Physics is the knowledge of nature. If we want to understand the matter at miscellaneous levels, let’s say both macroscopic and microscopic levels, basic Physics turns out to be a gold mine to study their nature of motion, behavior in low and high temperatures, the kinetic energy of molecules, and much more.
Physics helps us study the motion, behavior of matter through space and time. On the whole, it is a natural science that deals with all the related entities of force and energy.
Definition of Physics
Physics is a natural science that deals with matter and energy and interactions of matter with one another. It also deals with all physical processes and phenomena of a particular system.
Let’s suppose that there is a container filled with gas and on the top of this container, a frictionless movable piston is fitted. Now, on passing heat to this system, the gas expands. So, what is the Physics behind this expansion?
Well! When the heat is added, there is a temperature rise in the gas, which leads to the rise in the internal energy of the gas, and that internal energy is the kinetic energy. Initially, these gas molecules had a stored internal potential energy and they gain entropy because this potential energy converts into kinetic energy. This results in the expansion of the gas, and therefore, uplifting of the piston.
So, what do we infer from the above statement?
Well! Whatever energy was supplied got totally transformed into work, i.e., no wastage of energy. The same scenario is observed in an imaginary engine, viz: Carnot engine.
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So, our first law of thermodynamics (energy is transformed without creating or destroying it) with the help of Physics.
Definitions of Physics
Let’s have a look at a few Physics definition and branches:
1. Forces in Nature
Every day we observe the applications of forces in one or other objects like contact forces between two objects, frictional force between your shoes and the road, forces exerted on strings and springs, viscous forces, electrostatic and magnetic forces and much more; all these forces we encounter at the macroscopic world are manifestations of the following two types of forces:
Gravitational forces
Electromagnetic forces
However, at the microscopic level, we have two basic types of forces:
Strong nuclear forces
Weak nuclear forces
2. Ampere
The unit Ampere was named after a French Physicist and Mathematician named André-Marie Ampère. It is the SI unit of current.
The International System of units describes ampere in other terminologies by assuming it as the electromagnetic power an electrical circuit holds through which the current is flowing when the conductor is subjected to the potential difference across its ends. The dimensional formula for the current is [A].
Branches of Physics
There is a big list of branches in Physics basic, let’s enlist these:
Mechanics
Modern physics
Thermodynamics
Classical physics
Electricity
Magnetism
Geo physics
Plasma physics
Optics
Sound and oscillation
Chemical physics
Engineering physics
Quantum physics
Electronics
Nuclear physics
Particle physics
Biophysics
Astrophysics
Condensed matter physics
Solid-state physics
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Let’s discuss the basics of Physics in detail:
Physics Definition and Branches
FAQs on Basic Physics: Definitions, Branches, and Applications
1. What is the basic definition of Physics?
Physics is the natural science that studies matter, its fundamental constituents, its motion and behaviour through space and time, and the related entities of energy and force. In essence, it is the study of how the universe behaves, from the smallest subatomic particles to the largest galaxies. It seeks to understand the fundamental principles governing the physical world.
2. What are the two main branches of Physics?
The two primary branches of Physics are:
- Classical Physics: This branch deals with macroscopic phenomena and includes theories that predate the year 1900. It covers concepts like Newton's laws of motion, thermodynamics, and Maxwell's theory of electromagnetism, which are observable in our everyday world.
- Modern Physics: This branch deals with microscopic phenomena, often at very high speeds or on an atomic/subatomic scale. It is primarily based on the two major theories of the 20th century: relativity and quantum mechanics.
3. What is the key difference between Classical Physics and Modern Physics?
The key difference lies in the scale and conditions they describe. Classical Physics provides an accurate description of the motion of objects that are large relative to atoms and move at speeds much slower than the speed of light. In contrast, Modern Physics is required to explain the behaviour of matter at the atomic and subatomic levels (quantum mechanics) and phenomena occurring at or near the speed of light (relativity).
4. What are some of the fundamental sub-branches of Physics?
Beyond the two main branches, Physics is divided into several specialized fields of study. Some of the most fundamental sub-branches include:
- Mechanics: The study of motion and the forces that cause it.
- Thermodynamics: The study of heat, work, and temperature, and their relation to energy.
- Optics: The study of the properties and behaviour of light.
- Electromagnetism: The study of electric and magnetic fields and forces.
- Atomic and Nuclear Physics: The study of the structure and properties of atoms and their nuclei.
5. How does the study of basic physics apply to everyday life?
Basic physics principles are fundamental to countless everyday technologies and activities. For example, the principles of electromagnetism power our homes and electronic devices. Mechanics explains how cars move and why bridges stand. Thermodynamics is crucial for refrigeration and engines. Even a simple act like using a lever or seeing your reflection involves core concepts of physics.
6. What are the four fundamental forces in Physics?
Physics identifies four fundamental forces or interactions that govern how objects and particles interact. These are:
- The Gravitational Force: The force of attraction between any two masses.
- The Electromagnetic Force: Acts between electrically charged particles.
- The Strong Nuclear Force: Binds protons and neutrons together in the atomic nucleus.
- The Weak Nuclear Force: Responsible for certain types of radioactive decay.
7. Why is Physics often called the fundamental science?
Physics is considered the fundamental science because its principles and laws underpin all other natural sciences, including chemistry, biology, and geology. Chemical reactions are governed by the electromagnetic forces between atoms and molecules. Biological processes, from nerve impulses to metabolism, rely on physical and chemical phenomena. Therefore, a basic understanding of physics is essential for a deep understanding of these other fields.
8. What core concepts should a beginner focus on when starting to learn Physics?
A beginner starting with Physics should focus on understanding a few core concepts that form the foundation for more advanced topics. These include understanding fundamental quantities like mass, length, and time; the concepts of force and motion (as described by Newton's Laws); the principles of work, energy, and power; and the basic properties of matter and waves. Mastering these basics is crucial for building a strong foundation in the subject.

















