1. Chapter 3
Propagation of Light

2. Propagation of Light
Formation of shadows
The shadow cast by a point source of light
The shadow cast by an extended source of light
Eclipses
The colours in sunlight
The Pin hole cameraght is necessary for the growth of plants

3. Propagation of Light
Light travels in a straight line.This is called Propagation of Light.
Activities

4. Formation of shadows
The shadow cast by a point source of light
The shadow cast by an extended source of light

5. Eclipses
Solar eclipses-if the moon comes between the sun and the earth and the three are in a straight line,the shadow of the moon falls on the earth,then solar eclipse takes place.

6. Lunar eclipses-if the earth comes in between the sun and the moon,the shadow of the earthfalls on the moon,then lunar eclipse takes place.

7. COLOURS IN SUNLIGHT
Violet
Indigo
Blue
Green
Yellow
Orange
Red

8. The pin hole camera

9. Light is necessary growth of plants

10. QUESTION HOUR
1Define linear propagation of light
2Eclipses
3Why does an object cast a shadow on a screeen?
4Give reason-The Penumbra is faint.
Define umbra and penumbra.