In Young's double-slit experiment, the wavelength of light was changed from `7000 Å` to 3500 Å`. While doubling the separation between the slits, which of the following is not true for this experiment?

Options

A. The width of fringes changes.
B. The colour of bright fringes changes.
C. The separation between successive bright fringes changes.
D. The separation between successive dark fringes remains unchanged.

Answer

D

Explanation

As `beta=(lambdaD)/(d)`,
Therefore, when `lambda` is hlaved and d is doubled, `beta` becomes `(1)/(4)^(th)`. The separation between successive dark fringes reduce. It does not remain unchanged.