In Young.s double slit experiment the separation d between the slits is 2mm, the wavelength `lambda` of the light used is `5896 A^(0)` and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is `0.20^(0)`. To increase the fringe angular width to `0.21^(0)` (with same `lambda` and D) the separation between the slits needs to be changed to

Options

A. `1.8mm`
B. `1.9 mm`
C. `1.7 mm`
D. `2.1mm`

Answer

B