Question

On what factors does the refractive index of a medium depend?

Answer 1

Hint: The refractive index of a medium is the ratio of the velocity of light in vacuum to the ratio of velocity of light in that medium. It is denoted by and is given by , where c is the velocity of light in vacuum and v is the velocity of light in that medium.

Complete step by step solution:
The refractive index of a medium generally depends upon the following things
(1). The wavelength of light: The refractive linearly varies with the wavelengths because different wavelengths interact at different extents with the atoms of the medium. We know that at a certain frequency, wavelength of light is directly proportional to the velocity and thus also affects the refractive index and is inversely proportional to it. So, for shorter wavelengths we get greater refractive index and vice-versa.
(2). Density of medium: Denser mediums have viscosity higher than those which are less dense which causes light to travel slower. So, if the density of a medium is high, it will have a low refractive index and vice- versa.
(3). Temperature: We usually determine refractive index at standard temperature. At higher temperature, the density of the medium decreases and makes it less viscous resulting in a lesser refractive index and a greater refractive index when the temperature is low.

Additional Information:
Refractometer is a device that is popularly used to determine the refractive index of a fluid medium.

Note: The surrounding medium also comes into play when we talk about the refractive index of a medium. But as we talk about only a particular medium, we note only the properties associated with that medium only.