Question

1. What does the acronym LASER stand for? What characteristic of a laser makes it suitable for today's experiment?

2. What is meant by constructive and destructive interference?

3. Why do you see colors when you look at reflected light from a CD or DVD disk, or when you look at a soap bubble or oil film on water?

4. What do you think causes the colors on the artwork panels on the side of HLS2 (Health Sciences building) which change with time of day and the angle from which you view them?

Answer 1

LASER - Light amplification by stimulated emission of radiation.

Main specialities of LASER are monochromaticity, directionality, coherence, and high brightness

When two waves meet in such a way that the high amplitudes of a wave ( the crests ) add up together algebraically , then it's called constructive interference. The resulting wave has a higher amplitude. In destructive interference, amplitudes of a wave ( the crests ) of one wave meets the low amplitudes of a wave ( trough ) of another, and the result is a lower total amplitude. which is destructive interference

The colors when you look at reflected light from a CD or DVD disk, is due to constructive & destructive interference

The phenomenon refraction, where the light bends to change the wavelegth is the cause the colors on the artwork panels