B.E.

Scoring a good score in JEE Mains requires a thorough understanding of the material covered on the exam. Here are some of the important chapters that you should focus on while preparing for JEE Mains:
Mathematics: Algebra Trigonometry Coordinate Geometry, Calculus and Vector
Physics: Mechanics, Thermodynamics Waves and Optics Electromagnetism and Modern Physics
Chemistry: Physical Chemistry Organic Chemistry and Inorganic Chemistry
It's important to note that these are general guidelines and the specific topics and chapters that you should focus on may vary depending on your strengths and weaknesses. It's also important to practice as many sample papers, previous year question papers and mock tests as possible, this will help you to identify the areas you need to improve on and focus your studies accordingly. Additionally, a good time management during the exam is crucial, so you could finish the exam within the time frame. Keep in mind that, practicing and understanding the concepts is more important than just mugging up the formulas.

For Physics important topics are Heat and Thermodynamics Optics electrodynamics, modern Physics and mechanics are all important topics in Physics.
For Chemistry important topics are Alkanes, alkynes, polymers, carbonyls, and other organic Chemistry chapters are the most popular as per JEE Main. P-block elements and coordination compounds have become more prominent in inorganic Chemistry. Then came questions about metallurgy, chemical bonding, and so on.
For mathematics regular practice is required. Differential calculus has dominated JEE Main Mathematics question papers in recent years, followed by coordinate geometry. A lot of questions were asked about topics like integral calculus, vector analysis, 3D geometry, and so on. Other key topics that students should prepare for include Matrices and Determinants Statistics and the binomial theorem.