Question

(a) What do you understand by total internal reflection? Explain with the
help of a diagram and highlight the conditions under which it takes place?​

Answer 1

Explanation:

when a ray of light travels from denser higher refractive index medium (say water)

to medium of comparatively lower refractive index (say air)

the ray of light goes away from the perpendicular

means angle of refraction is more than angle of incidence

If we go on increasing the angle of incidence gradually at a certain angle the ray gets reflected in the same medium here water, and it continues for larger angles. This phenomenon is known as total internal reflection.

I think this will help you

( Sorry I don't have the diagram)