Question

A wave passes into a different medium with an increase in speed. The ratio of the angle of incidence to the angle of refraction, defined arbitrarily here as R, is?

a) R=0
b) 1>R>0
c) R=1
d) R>1

Answer 1

(d) R>1

Step-by-step explanation:

Let the wave is passing from the medium
`M_1` to medium
`M_2` as shown in the figure.

Given that there is an increase in the speed in the medium
`M_2` , this is only due to the fact that medium

As when light passes from denser to rare medium, it moves away from the normal as shown in the figure.

So, the angle made by light rays with the normal in the rare medium, angle of refraction
`r`, is more than the angle made by light rays with the normal in the denser medium, angle of incident
`i`.

Hence, r>i

`\Rightarrow \frac r i >1`

`\Rightarrow R >1` [as r/i = R]

Hence, option (d) is correct.