Answer to Question #152357 in Physics for joy

Question

a. Draw a diagram to show the path of a ray of light travelling from air into a
rectangular glass block at an angle of about 45°.
b .Show the path of the ray as it emerges from the block.
c. Explain why the ray changes direction each time it crosses the air/glass
boundary.
d .Draw a second diagram showing a ray that travels through the block
without its direction changing.

Answer 1

If the ray of light is directed at an angle to the surface, and the angle is not 90° to the surface (or 0° to the perpendicular to the surface), the ray changes direction each time it crosses the air/glass boundary because the refraction indexes of air and glass are different, and according to Snell's law, the ray of light will experience refraction.

If the angle to the perpendicular to the surface is 0°, sine of 0° is 0 and no changes in direction occur.