Let A(1, 2, -3) and B(-1, -2, 1) are two vectors. Direction cosines of the vector joining the vector in the direction A to is ……………….

Options

A. There would be no interference pattern on the second screen but it would be lighted.
B. The second screen would be totally dark.
C. There would be a single bright point on the second screen.
D. There would be a regular two slit pattern on the second screen.

Answer

D

Explanation

There would be a regular two slit pattern on the second screen.
Point `P_(2)` shown in figure (where there is a hole) is a point on the wavefront and so it behaves like a secondary source and so it emits light waves which are incident on slits `S_(3)` and `S_(4)`. Here these two slits are illuminated at the same time by same wavefront. Hence they behave like coherent sources and so they produce stationary interference on the second screen kept behind them like YDSE (Young.s Double Slit Experiment).