Light

 

1. Introduction to Light

 

Light is a form of energy that enables us to see objects.

 

It travels in straight lines (rectilinear propagation).

 

Speed of light in vacuum = 3 × 10⁸ m/s.

 

 

2. Properties of Light

 

Reflection

 

Refraction

 

Dispersion

 

Scattering

 

 

3. Reflection of Light

 

Laws of reflection:

 

1. Angle of incidence = Angle of reflection

 

 

2. Incident ray, reflected ray, and normal lie in the same plane.

 

 

 

Types of mirrors: plane, concave, convex.

 

Uses in daily life (rear-view mirror, torch, shaving mirror).

 

 

4. Refraction of Light

 

Bending of light when it passes from one medium to another.

 

Examples: pencil in water appears bent, twinkling of stars.

 

Lenses: convex (converging) & concave (diverging).

 

Applications: spectacles, microscope, camera.

 

 

5. Dispersion of Light

 

Splitting of white light into 7 colors (VIBGYOR) by a prism.

 

Example: rainbow formation.

 

 

6. Scattering of Light

 

Spreading of light in all directions by particles.

 

Sky appears blue (short wavelength scattered more).

 

Red

color of sunrise and sunset (longer wavelength reaches us).