You are given four sources of light each one providing a light of a single colour-red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is `90^@`. Which of the following statements is correct it the source of yellow light is replaced with that of other lights without changing the angle of incidence ?

Options

A. The beam of red light would undergo total internal reflection.
B. The beam of red light would bend towards normal while it gets refracted through the second medium.
C. The beam of blue light would undergo total internal reflection.
D. The beam of green light would bend away from the normal as it gets refracted through the second medium.

Answer

C

Explanation

When angle of incidence (i) = Critical angle `(i_(c))`. Then angle of refraction (r) = `90^(@)` for the yellow light. As angle of incidence is same, then `i_(c)`, should be smaller for the occurrence of total internal reflection.
As, `mu=(1)/(sin i_(c))`
`therefore i_(c)` will be smaller when refractive index `(mu)` for a colour is large.
The blue colour corresponds to a larger value of `mu` (as its wavelength is smaller) and hence, a smaller value of the critical angle `i_(c)`. The correct option is (c).