Question

The second law of refraction states that:
A. \[\dfrac{{{{\sin }^2}i}}{{{{\sin }^2}r}} = \mu \]
B. \[\dfrac{{\sin i}}{{\sin r}} = \mu \]
C. \[\dfrac{{\sqrt {\sin i} }}{{\sqrt {\sin r} }} = \mu \]
D. None of these are true

Answer 1

Hint: When the light passes through one optically transparent medium to another transparent medium of different refractive index, it undergoes a deviation from its original path. The second law relates the angle of incidence and angle of refraction with the refractive index of the medium.

Complete answer:
We know that when the light passes through one optically transparent medium to another transparent medium of different refractive index, it undergoes a deviation from its original path. This phenomenon is termed as refraction of light.Let us define the angle of incidence and angle of refraction. We know that the angle made by the incident ray with the normal is known as angle of incidence and the angle made by the refracted ray with the normal is known as angle of refraction.

According to the second law of refraction, we have, the ratio of sine of angle of incidence to the sine of angle of refraction is a constant. The constant is known as the refractive index of the medium. This law is known as Snell’s law and it can be expressed as,
\[\dfrac{{\sin i}}{{\sin r}} = \mu \]
Here, i is the angle of incidence and r is the angle of refraction.
We know that, greater the refractive index \[\mu \], greater the light ray bends towards the normal and the second medium is denser than the former medium.

So, the correct answer is option B.

Note: The refractive index \[\mu \] is the ratio of refractive index of the second medium to the refractive index of the first medium. Thus, if the second medium has a greater refractive index than the first medium, the second medium is optically denser medium than the first medium. Students can also express the refractive index as the ratio of speed of light in the vacuum to the speed of the light in the given medium.