Hey Nilesh.

Here is a list of important topics for JEE mains and their respective weightages.

Maths-

Percentage Co-Ordinate Geometry 17%

Calculus 27%

Algebra 27%

Vector/3-D Geometry 10%

Trigonometry 6%

Sets Relations, Mathematical Reasoning, Statistics 13%

Physics-

Mechanics 30%

Heat Thermodynamics 7%

Electrostatics Current Electricity 17%

Magnetics Electro Magnetic Induction 13%

Optics Waves 3%

Modern Physics 10%

Simple Harmonic Motion, Waves Elasticity 7%

Semi-Conductor Devices, Electromagnetic Waves and Principles of Communication 13%

Inorganic Chemistry- Classification of Elements and Periodicity in Properties, General Principles and Process of Isolation of Metals, Hydrogen, s - Block Elements (Alkali and Alkaline Earth Metals), Co-ordination Compounds, Environmental Chemistry to name few.  

Organic Chemistry- Purification and Characterisation of Organic Compounds, Some Basic Principles of Organic Chemistry, Hydrocarbons,Organic Compounds Containing Oxygen, Organic Compounds Containing Nitrogen, Bio Moleculesetc.  

Physical Chemistry- Some Basic concepts in Chemistry,States of Matter, Atomic Structure, Chemical Bonding and Molecular Structure,Chemical Thermodynamics, Equilibrium, Surface Chemistry,Chemical Kinetics and Redox Reactions and Electrochemistry.