Question

In a light interference pattern, alternate dark and bright fringes are seen. Why are the bright fringes formed?

a) no interference
b) too much interference
c) destructive interference
d) constructive interference

Answer 1

The light interference pattern is a series of light and dark stripes.

The bright stripes are areas where there is CONstructive interference.

The dark stripes are areas where there is DEstructive interference.

Answer 2

The correct choice is

d) constructive interference

bright fringes are formed as a result of constructive interference between the two waves. Constructive interference takes place between the two waves when crest of one wave falls on crest of another wave or trough of one wave falls on trough of another wave. the new wave thus produced has higher amplitude than any of the two waves. that is how we get bright fringes.