1. Solar energy
Sun power

2. Energy obtain from sun is called solar energy.
sun is an natural source of energy.
Hydrogen (71%)
Helium (26.5%)
Other gasses (2.5%)

3. Types of sun rays/radiations:-
Ultraviolet rays
Visible rays
Infrared rays

4. Ultraviolet rays:-
It has the short wave length and absorbed by upper layer of atmosphere.
Visible rays:-
It is the visible light and consist of seven colours.
Infrared rays:-
It has the longest wave length. It is main source of heat. There are also called heat rays.

6. Major uses of solar energy:-
Daylight
Agricultural product
Water heating
Generating electrical power
photovoltaics cell

7. Photovoltaics cell:-
It is a semiconductor device that convert sunlight energy into electrical energy is called solar cell/photovoltaics cell. It is made by p- type and N-type semicomductors materials.

8. Energy Generating by photovoltaics cell
When sun rays fall on the top layer of p-type semiconductor material and reach into lower N-type semiconductor material these rayer are absorbed by the semiconductor matrial and electrons hole pair are generated,and electric field is made across the material. The electrons are allways to move in particular direction only from P-type mateial to N-type material.

10. Advantage 0f solar energy:-
Renewable energy source
Pollution free
No fuel cost
Runing cost is negiligble
No maintance cost

11. Disadvantage of solar energy:-
Installation cost is high
Required large area of land
The obtain energy is not constant