# JEE Main Physics: 17 Concepts You Need to Know

Statistics have always suggested that in general, among all the three subjects, students struggle when it comes to scoring high in Physics. The average score of most of the students is lowest in Physics. Here we are, trying to list down some topics which are very important for JEE Main Physics, which will help you to prepare in a smarter way.

Broadly, we can divide JEE Physics into 5 parts:

• Mechanics
• Thermodynamics
• Electrodynamics and Magnetism
• SHM & Wave Motion
• Optics & Modern Physics

## JEE Main Physics: Mechanics

• Kinematics: The very first topic of JEE Physics and the beginning of such a vast unit is Kinematics. It has various subtopics which includes Vector, Rectilinear Motion, Motion in two dimensions, and relative motion. From past few years, JEE is more focusing on giving graph-type questions from such topics and 1 question is expected every year. You should also focus on 3 equations of motion and projectile motion.
• NLM and Friction: Again, 3 laws of motion are must, not only for covering this topic, but complete Mechanics is based on these 3 laws and each and every topic requires their fundamental knowledge. You should have an understanding of how to solve friction, string, spring-type problems.
• Center Of Mass and Work, Power & Energy: 1-2 questions are expected from these topics covering the main concepts like Conservation of Momentum, applying energy conservation laws, calculating work-done, power, the potential for different functions of Force, time, distance. You must know the derivations of calculating COM of simple bodies and must remember their formulae as well.
• Rotational Motion: Rotation is a vast topic which tests your skills of whole Mechanics. But generally JEE Main probably asks just 1 question from it.So you can focus on concepts like Moment of Inertia, Conservation of Angular Momentum from which questions are being asked.
• Gravitation: This topic has fluctuating weightage in JEE Main, but still one can expect 1-2 questions in the Paper.
Important concepts are Universal Law of Gravitation, Kepler’s Law, Gravitational Potential Energy, Escape Velocity, Binding Energy.
• Fluids & Properties of Matter: These topics also come under Mechanics and are important for JEE Main Physics.Important concepts are Viscosity, Surface Tension, Bernoulli’s Theorem, Torricelli’s Law, Concept of Terminal velocity
• Error in Measurement(Practical Applications): From last few years, JEE has started asking practical based questions.Questions on this topic are now being asked very frequently and you can easily fetch marks from this portion by doing rigorous practice.Important concepts for this topic are related to Significant figures, Vernier Calliper, Screw Gauge, Potentiometer & Sonometer experiment.

## JEE Main Physics: Electrodynamics

This is the most important unit for JEE Main Physics.It covers about 25% of weightage of JEE Main Physics Paper.This unit comprises of topics like:

• Current Electricity: Almost 4 questions are being asked from this topic every year in JEE Main.This makes it very important.You should be well aware of Kirchhoff’s Law, various techniques for solving resistance network problems, Problems on Galvanometer.
• Electrostatics & Capacitors: This is again an important part of Electrodynamics unit.It covers about 10% weight of JEE Main Physics Paper. You should be thorough with the concepts of Coulomb’s Law, Electric Field, Electric Potential due to various geometrical setups, Energy Conservation, Electric Dipole, Problems on Capacitors.
• ElectroMagnetic Field & Induction: This topic covers important concepts like Biot-Savarts Law, Magnetic Flux, Magnetic field due to current for various geometrical setups, Magnetic Dipole, Lenz’s Law.These all topics require practice and you can grab marks easily.

## JEE Main Physics: Thermodynamics

This unit approximately covers 13% of JEE Main Physics paper and is again very important.
We can divide this unit into 3 Major parts.

• Laws of Thermodynamics: This topic covers all the basic concepts of thermodynamics and you should be thorough with all of them.Thermodynamics is a bit tricky unit in itself and requires more effort to get the feel of the topic.You should be well acquainted with all 3 laws of Thermodynamics, Carnot Cycle, Thermodynamics state variables, Thermodynamic Processes, P-V-T diagrams.
• Kinetic Theory of Gases: You can develop a good hold on this topic by doing rigorous practice.Important concepts are degrees of freedom, specific heat for different processes.You should be well aware of all the assumptions of the kinetic theory of gases.
• Calorimetry and Thermal Expansion: This is a topic in which you can fetch some easy marks.You need to be thorough with all the formulae, have a good amount of practice.This is sufficient to score in this topic.

## JEE Main Physics: SHM and Sound Waves

These both units covers about 10% of JEE Main Physics paper.You should know how to calculate time period of SHM for various assemblies, Phasor technique, Relation between Kinetic energy, Potential Energy.

Waves in itself is a very vast topic and have many subtopics.For JEE Main Physics, you can focus on equations of the wave in sinusoidal form, harmonics of a wave, Pressure and density variations for a wave, Doppler Effect.

## JEE Main Physics: Optics & Modern Physics

These two units are very very important for JEE Main Physics.Both units cover about 17-19% of the Physics Paper, with Modern Physics being more important.

For Ray Optics you should be thorough with the concepts of Reflection, Refraction, Total Internal Reflection, Snell’s Law, Geometrical Optics.
In Wave Optics you should be well acquainted with Huygens theory, Diffraction principle, Polarisation of light, Brewster’s law.

For Modern Physics you should have a grip on concepts of Atomic structure, Bohr Model of Hydrogen atom, Threshold energy, De-Broglie explanation of the matter, Nuclear Physics, X-Rays.

This was theoretical description about all the important topics for JEE Main Physics. JEE Main Physics is more about speed,accuracy and practice. It is a strong recommendation that you should memorise the standard results, formulae of each topic. This is a must to score good in physics.

Lastly you should also practice previous years’ question papers. They are very important.
All the best!