Important Chapters For Physics

Wave Optics

Heat and Thermodynamics

Electromagnetic Waves

Semiconductors

Ray Optics

Gravitation

Photoelectric Effect

Oscillations

Important Chapters For Chemistry

Atomic Structure

Electrochemistry

Nuclear and Surface Chemistry

d-Block Elements

Alkyl Halides

Aromatic Compounds

Gaseous and Liquid States

Chemical Kinetics

Chemical Bonding

Coordination Compounds

Important Chapters For Mathematics

Vectors

3-Dimensional Geometry

Sequence and Series

Determinants and Matrices

Straight Lines

Circle

Probability Distribution

for physics :-

• electrodymanics
• mechanics
• modern physics

for chemistry:-

• physical chemistry 1 or 2
• inorganic chemistry (chemical bonding, periodic table and periodicity, S-block)

for mathematics:-

• differential calculus
• integral calculas 
• coordinate geometry

These are the main topics that carry most weightage and whwn answered correctly you can easily score above 100. All the best!!