Question

Define refractive index and state Snell’s law of refraction.

Hint:

Snell’s law can also be written as: \[ n_1 \sin i = n_2 \sin r \] where \(n_1\) and \(n_2\) are the refractive indices of the two media.

Answer 1

Concept: When light travels from one medium to another, its speed changes and the ray bends at the boundary. This phenomenon is known as refraction of light. The refractive index and Snell’s law describe this behavior quantitatively.
Step 1:Refractive Index} The refractive index of a medium is defined as the ratio of the speed of light in vacuum to the speed of light in that medium. \[ n = \frac{c}{v} \] where \(n\) = refractive index of the medium \(c\) = speed of light in vacuum \(v\) = speed of light in the medium
Step 2:Snell’s Law of Refraction} Snell’s law states that when a ray of light passes from one medium to another, the ratio of the sine of the angle of incidence (\(i\)) to the sine of the angle of refraction (\(r\)) remains constant. \[ \frac{\sin i}{\sin r} = \text{constant} \] This constant is called the refractive index of the second medium with respect to the first medium.