Name: Applications of TIR: Mirage and Looming
Uploaded: 2019-07-19
Duration: 4 min 7 s
Description: Let’s learn about mirages and looming in this interesting video. These are fascinating phenomena of light observed on hot summer days.

Question

State the laws of refraction. Distinguish between absolute refractive index and refractive index of a medium. Show that $n = \frac{c}{v}$ , where letters have usual meanings.

Accepted Answer

Laws of refraction: Snell experimentally obtained the following laws of refraction:

(i) The incident ray, the refracted ray and the normal to the interface at the point of incidence, all lie in the same plane.

(ii) The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. Hence:

$n_{21} = \frac{\sin i}{\sin r}$ .......(i)

Where, $n_{21}$ is constant, called the refractive index of the second medium with respect to the first medium. This is called the relative refractive index. $n_{21}$ is the characteristic of the pair of media. When the first medium is air or vacuum, then it is called the absolute refractive index of the second medium. Hence, the absolute refractive index is the refractive index of a medium with respect to air or vacuum.

The relative refractive index of a material in terms of speed of light in two media $v_{1}$ and $v_{2}$ can be written as:

$n_{21} = \frac{v_{1}}{v_{2}} = \frac{\sin i}{\sin r}$ ......(ii)

If the speed of light in the second medium is $v$ then $v_{2} = v$ and if the first medium is air then $v_{1} = c$ . Using (i), the absolute refractive index of the given material:

$n_{21} = \frac{c}{v}$ .....(iii)

State the laws of refraction. Distinguish between absolute refractive index and refractive index of a medium. Show that $n = \frac{c}{v}$ , where letters have usual meanings.

Important Questions on Refraction of Light at a Plane Interface : Total Internal Reflection : Optical Fibre

Learn and Prepare for any exam you want !

State the laws of refraction. Distinguish between absolute refractive index and refractive index of a medium. Show that n=cv, where letters have usual meanings.

Important Questions on Refraction of Light at a Plane Interface : Total Internal Reflection : Optical Fibre

Learn and Prepare for any exam you want !

State the laws of refraction. Distinguish between absolute refractive index and refractive index of a medium. Show that $n = \frac{c}{v}$ , where letters have usual meanings.