The optical path difference between two identical light waves arriving at a point is $31.5 \lambda$, where…
The optical path difference between two identical light waves arriving at a point is $31.5 \lambda$, where $\lambda$ is the wavelength of light used. The point is [Given: Two light sources are coherent]
alternative bright and dark.
dark.
bright.
neither bright nor dark.
Solution
Path difference $\Delta x=(63) \frac{\lambda}{2}$, which is an odd multiple of the half wavelength. Therefore, it is a dark point or the point of destructive interference.