What is Refraction of Light?
Refraction of light is the phenomenon where light changes its direction when it passes from one transparent medium to another, resulting in a change in its speed. This bending of light occurs because light travels at different speeds in different media such as air, water, or glass.
When a ray of light travels from one medium to another at an angle other than 90°, the change in speed causes the ray to change direction at the boundary between the two media. This change in direction is called refraction.
For example, when a pencil is placed partly in water, it appears bent or broken at the water surface due to refraction. This is because light rays coming from the pencil bend when they pass from water to air, altering the apparent position of the pencil.
Key Points About Refraction:
- Refraction occurs when light passes from one medium to another with a different optical density.
- It causes the light ray to bend towards or away from the normal (an imaginary line perpendicular to the surface) depending on whether the light is entering a denser or rarer medium.
- The amount of bending depends on the refractive indices of the two media.
- Refraction is responsible for phenomena such as the apparent bending of objects in water, formation of rainbows, and focusing of light by lenses.
Laws of Refraction:
- The incident ray, refracted ray, and the normal to the interface of two media 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 for a given pair of media, known as the refractive index.
Mathematically,
Where i is the angle of incidence, r is the angle of refraction, and μ is the refractive index.
Importance of Refraction:
Refraction helps in the functioning of lenses used in glasses, cameras, microscopes, and telescopes. It also explains many natural phenomena like the formation of rainbows and mirages.
In summary, refraction of light is a fundamental concept that explains how light bends when traveling between different transparent materials, influencing how we see the world and enabling many optical devices.