Question

Write the laws of refraction of light.​

Answer 1

$\huge \fbox \red{Answer}$

Laws of refraction state that:

• The incident ray refracted ray, and the normal to the interface of two media at the point of incidence all lie on the same plane.

• The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. This is also known as Snell's law of refraction

Answer 2

‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎Laws of Refraction of Light

Laws of Refraction, also known as Snell's law of Refraction are given as below as :

• 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 the sine of the angle of incidence to the sine of the angle of refraction is a constant for a light of given colour and for the given pair of media.

If $\sf i$ is the angle of incidence and $\sf r$ is the angle of refraction, then

‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎‎ ‎ ‎ ‎ ‎ ‎ ‎$\sf \dfrac{sin\: i}{sin \: r}= constant$

This constant is called the refractive index of the second medium with respect to the first medium. It is generally represented by the Greek letter, $\sf _1 \mu_2$(mew).

Note : The refractive index has no unit as it is the ratio of two similar quantities.

The refractive index of a medium is also defined in terms of speed of light in different media.

$\sf \mu = \dfrac{\textsf{Speed of light in vaccum or air (c)}}{\textsf{Speed of light in the medium (v)}}$

In general,

${\sf _1 \mu_2= \dfrac{\textsf{Speed of light in medium 1}}{\textsf{Speed of light in medium 2}}}$