What are the laws of refraction
Answers
The incident ray, refracted ray and the normal; at the point of incidence all lie in the small plane.
The ratio of sine of angle of incidence with sine of angle of refraction is always equal to relative refractive index of medium 2 with respect to medium 1.
Explanation:
Law of Refraction
The law of refraction, which is generally known as Snell's law, governs the behaviour of light-rays as they propagate across a sharp interface between two transparent dielectric media.
Consider a light-ray incident on a plane interface between two transparent dielectric media, labelled 1 and 2, as shown in Fig. 57. The law of refraction states that the incident ray, the refracted ray, and the normal to the interface, all lie in the same plane. Furthermore,
\begin{displaymath}
n_1\,\sin\theta_1 = n_2\,\sin\theta_2,
\end{displaymath} (341)
where $\theta_1$ is the angle subtended between the incident ray and the normal to the interface, and $\theta_2$ is the angle subtended between the refracted ray and the normal to the interface. The quantities $n_1$ and $n_2$ are termed the refractive indices of media 1 and 2, respectively. Thus, the law of refraction predicts that a light-ray always deviates more towards the normal in the optically denser medium: i.e., the medium with the higher refractive index. Note that $n_2>n_1$ in the figure. The law of refraction also holds for non-planar interfaces, provided that the normal to the interface at any given point is understood to be the normal to the local tangent plane of the interface at that point.
