A small bulb is placed at bottom of a tank containing water to depth 80cm||Physics 12th Optics ncert

A small bulb is placed at bottom of a tank containing water to depth 80cm. What is the area of the surface of water through which light from the bulb can emerge out? Refractive index of water is 1.33. Consider the bulb to be a point source.
Chapter :9, Ray optics and optical Instruments
Class 12th
Subject Physics
Book NCERT
Question Number 9.5 NCERT Exercise Class 12th Chapter 9 Ray optics and Optical Instruments.
Channel Physics Love
By SFIC Academy