Question

A green light is incident from the water to the air - water interface at the critical angle (θ). Select the correct statement.

(a) The entire spectrum of visible light will come out of the water at an angle of 90º to the normal.

(b) The spectrum of visible light whose frequency is less than that of green light will come out to the air medium.

(c) The spectrum of visible light whose frequency is more than that of green light will come out to the air medium.

(d) The entire spectrum of visible light will come out of the water at various angles to the normal.

Answer 1

Correct Option (b) The spectrum of visible light whose frequency is less than that of green light will come out to the air medium.

Explanation:

If frequency is less, then λ is greater and hence RI n(water) is less and therefore critical angle increases. So, they do not suffer reflection and come out at angle less than 90° of the air medium.