Light: Reflection and Refraction Class 10 Notes - PDF & Key Formulas

1. Reflection of Light

Reflection is the phenomenon of bouncing back of light rays when they strike a polished surface (like a mirror).

Laws of Reflection

[Image of the laws of reflection of light]

• The angle of incidence is always equal to the angle of reflection (∠i = ∠r).
• The incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.

Spherical Mirrors

2. Mirror Formula & Magnification

These formulas are essential for solving numerical problems in the Class 10 boards.

(v = image distance, u = object distance, f = focal length)

3. Refraction of Light

The bending of light when it passes from one transparent medium to another due to a change in its speed.

Laws of Refraction (Snell’s Law)

• The incident ray, the refracted ray, and the normal all lie in the same plane.
• The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant:

Refractive Index (n)

Represents how much light slows down in a medium.

4. Lenses

Lenses work on the principle of refraction.

[Image of ray diagrams for convex and concave lenses]