In YDSE, let A and B be two slits. Films of thickness `t_(A)` and `t_(B)` and refractive `mu_(A)` and `mu_(B)` are placed in front of A and B, respectively. If `mu_(A) t_(A) = mu_(A) t_(B)`, then the central maxima will

Options

A. not shift
B. shift toward A
C. shift toward B
D. (b) if `t_(B) lt t_(A)` and (C ) if `t_(B) lt t_(A)`

Answer

d

Explanation

`Delta x = (mu_(A) - 1) t_(A) - (mu_(B) - 1) t_(B)`
`= mu_(A) t_(A) - mu_(B) t_(B) - t_(B) + t_(B)`
`= t_(B) - t_(A)`
If `Delta x gt 0`, the fringe pattern will shift upward.
If `Delta x lt 0`, the fringe pattern will shift downward.