While conduction the Young's double slit experiment, a student replaced the two slits with a large opaque plate in the x-y plane containing two small holes that act as two coherent point sources `(S_(1),S_(2))` emitting light of wavelength 600nm. The student mistakenly placed the screen parallel to the x-z plane `(for zgt0)` at a distance D=3 m from the mid-point of `S_(1)`,`S_(2)`, as shown schematically in the figure. The distance between the sources `d=0.6003 mm`. The origin O is at the intersection of the screen and the line joining `S_(1)S_(2)`. Which of the following is (are) true of the intensity pattern of the screen?

Options

A. semiciricular bright and dasrk bands centred at point O
B. Hyperbolic bright and dark bands with focisymmetrically plasced about O in the x-direction
C. The region very close to the point O will be dark
D. Straight bright and dark bands parallel to the x-axis.

Answer

A, C

Explanation

From theory fringes will be semicircular
and `(d)/(lambda) = 1000 + (1)/(2)`
So at 0 it will be dark.