Question

What is meant by refraction of light? State the laws of reflection.

Answer 1

- Hint: In this question some terms are very necessary and that are: The ray which falls on the surface of separation (or interface) to enter into the new medium are incident rays. The ray in the second medium, obtained after refraction, is a refracted ray. Imaginary straight line perpendicular to the refracting surface at the point of refraction. The angle between the incident ray and the normal are angle of incidence (i) and lastly angle of refraction i.e. the angle between the refracted ray and the normal.

Complete step-by-step solution -

Refraction: The phenomenon of change in the direction of light when it passes from one transparent medium to another is called refraction.
Laws of refraction:
The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane .
The ratio of sine angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media. This law is also known as Snell’s law of refraction.
If $i$ is the angle of incidence and $r$ is the angle of refraction, then,
${}^1{\mu _2} = \dfrac{{\sin \;i}}{{\sin \;r}}$
This constant value is called the refractive index of the second medium with respect to the first.

Note: When light is incident normally, only speed changes and direction of light remains the same. When light ray passes from a rarer medium to denser medium, it bends towards the normal. When light ray passes from denser medium to rarer medium, it bends away from the normal .