Question

when light passes from air into a denser medium like glass, it: slows down and bends away from the normal. slows down and bends toward the normal. speeds up and bends away from the normal. speeds up and bends toward the normal. the speed of light in plastic is 2 x10^8m/s calculate the index of refraction for plastic. (3marks) 0.6 1.5 2 4 which property of light is demonstrated when you see your reflection in a still pond? refraction dispersion reflection scattering

Explanation:

First Question

When light moves from a less - dense medium (air) to a denser medium (glass), according to the law of refraction:

• The speed of light decreases in the denser medium.
• The light ray bends towards the normal.

Second Question

The formula for the refractive index \(n\) is \(n=\frac{c}{v}\), where \(c = 3\times10^{8}\text{ m/s}\) (speed of light in vacuum) and \(v = 2\times10^{8}\text{ m/s}\) (speed of light in plastic)

$$ n=\frac{3\times 10^{8}}{2\times 10^{8}}=\frac{3}{2}=1.5 $$

Third Question

• Refraction: is the bending of light when it passes from one medium to another.
• Dispersion: is the separation of white light into its component colors.
• Reflection: is the bouncing back of light when it hits a surface. When you see your reflection in a still pond, light is bouncing back from the water - air interface (surface of the pond) to your eyes.
• Scattering: is the random deflection of light by particles.

Answer:

1. Slows down and bends toward the normal.
2. \(1.5\)
3. Reflection