Two source `S_(1)` and `S_(2)` of intensity `I_(1)` and `I_(2)` are placed in front of a screen [Figure a]. The pattern of intensity distribution see in the central portion is given by Figure b. In this case which of the following statement are true.

Options

A. `S_(1)` and `S_(2)` have the same intensities
B. `S_(1)` and `S_(2)` have a constant phase difference
C. `S_(1)` and `S_(2)` have the same phase
D. `S_(1)` and `S_(2)` have the same wavelength

Answer

A, B, D

Explanation

From the pattern of intensity distribution seen in the central portion, Fig. we find that
(i) as intensity of successive maxima is the same, `S_(1)` and `S_(2)`have the same intensity.
(ii) as width of successive maxima appears to increase slightly, `S_(1)`, `S_(2)` must have a constant phase difference. (iii) as minimum intensity is zero, `S_(1)`, `S_(2)` must have the same wavelength.
The choice (a), (b), (d) are correct.