Laws of Reflection and Refraction

In the study of geometric optics, understanding the laws of reflection and refraction is crucial. These laws govern the behavior of light as it interacts with different surfaces and mediums. Let's explore them in detail:

1. Law of Reflection

When a light ray strikes a smooth surface, such as a mirror, the angle of incidence (θᵢ) is equal to the angle of reflection (θᵣ). This means that the incident ray, the normal (a line perpendicular to the surface), and the reflected ray all lie on the same plane.

Example: Suppose a light ray is incident on a mirror at an angle of 30 degrees with respect to the normal. According to the law of reflection, the reflected ray will also make a 30-degree angle with the normal.

2. Law of Refraction (Snell's Law)

When a light ray passes from one medium to another, its direction changes due to change in speed. This change in direction is governed by Snell's law, which states that the ratio of the sines of the angles of incidence (θᵢ) and refraction (θᵣ) is equal to the ratio of the velocities of light in the two media (n₁ and n₂):

Example: If a light ray travels from air (n₁ = 1) to water (n₂ = 1.33) and the angle of incidence is 45 degrees, we can use Snell's law to find the angle of refraction.

These laws play a fundamental role in understanding the behavior of light and are essential for analyzing the formation of images in mirrors and lenses. By applying these principles, we can accurately predict how light rays interact with various surfaces and mediums.