Chemistry
Chemical Reactions and Equations
10 Topics Acids, Bases and Salt
7 Topics Metals and Non-Metals
16 Topics Biology
Heredity and Evolution
10 Topics Our Environment
7 Topics Physics
Light Reflection and Refraction
17 Topics The Human Eye and Colourful World
15 Topics Electricity
11 Topics Magnetic Effects of Electric Current
10 Topics 
Power of a Lens
[ Power of lens, Focal length (metre), Dioptre, Combination of lenses, Negative power, Positive power, Algebraic addition ]