In Young's double-slit experment, the frist maxima is observed at a fixed point P on the screen. Now, the screen is continously moved away from the plane of slits. The ratio of intensity at point P to the intensity at point O (center of the screen)

Options

A. Remains constant
B. Keeps on decreasing
C. first decreases and then increases
D. first decreases and then becomes constant

Answer

C

Explanation

The maxima at P becomes minima & then maxima alternately. But central bright fringe is always remain at O.