# AP Physics B Optics HELP

1. Feb 7, 2008

### baby_angel248

***ap Physics B Optics Help!!!!!!!!!!!!!!!!***

A point souce S of monochromatic light is located on the bottom of a swimming pool filled with water to a depth of 1.0 meter. The index of refraction of water is 1.33 for this light. Point P is located on the surface of the water directly above the light source. A person floats motionless on a raft so that the surface of the water is undisturbed.

1) Determine the velocity of the source's light in water

2) Determine the critical angle for the air-water interference

Suppose that a converging lens with a focal length of 30 centimeters in water is placed 20 centimeters above the light source and an image of the light source is formed by the lens.

3) Calculate the position of the image with respect to the bottom of the pool

ok... i can't even TRY to solve this thing... HELP!!

Last edited: Feb 7, 2008
2. Feb 7, 2008

### rl.bhat

ok... i can't even TRY to solve this thing... HELP!!
NO, you cann't say that. If you want know, please open the book. Find the relation between the velocity of light in air, in water and the refractive index of the water and the critical angle for the air-water interference