Question

The path difference between two light waves is 60. 5 wavelength. Is the point bright or dark ?​

Answer 1

Given:

Optical path difference=60.5

To find:

Is the point bright or dark

Solution:

For a minimum intensity fringe or a dark fringe to form, the path difference must be

Δ$x=(2n+1)$×λ/2

Δ$x=60.5$λ

where Δ$x$ is the path-difference,

=121(λ/2)

The above is an odd multiple of λ/2. Therefore, a minima will be formed and a dark fringe will appear.

Hence, the point will appear dark.