# Struggling with homework Question

1. Sep 8, 2009

### MikeDDD

Hi guys I have a take home assignment for physics and I really need to do well or I'm going to fail the semester and I just really need some help with some questions I'm really stressing. Any help would be so appreciated beyond belief!

Question 1:
A glass is half-full of water, with a layer of oil (n = 1.55) floating on top. A ray of light traveling downward through the oil is incident on the water at an angle of 73.8°. Take the refraction index of water to be 1.333.

(a) Determine the critical angle for the oil-water interface.

(b) Will the ray penetrate into the water? 1 = yes, 2 = no: Type the number of the correct answer.

Question 2:

A ray of sunlight is passing from diamond into crown glass; the angle of incidence is 31.00°. The indices of refraction for the blue and red components of the ray are: blue (ndiamond = 2.444, ncrown glass = 1.531), and red (ndiamond = 2.410, ncrown glass = 1.520).
Determine the angle between the refracted blue and red rays in the crown glass. Give your answer to two significant figures.

and the final question I just have no idea what to do, any help much appreciated.

Question 3:

A slide projector has a converging lens whose focal length is 119.00 mm. (a) How far (in meters) from the lens must the screen be located if a slide is placed 121.81 mm from the lens? If the slide measures 24.0 mm (height) x 36.0 mm (width), what are the magnitudes of the (b) width (in mm) and (c) height (in mm) of its image?

2. Sep 9, 2009

### MikeDDD

Can someone move my post to homework section. Apologies to all.

3. Sep 9, 2009

### Integral

Staff Emeritus