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

(a,b,d) Consider the pattern of the intensity shown in the figure.
(i) As intensities of all successive minima is zero, hence we can say that two sources `S_(1)` and `S_(2)` are having same intensitiess.
(ii) As width of the seccessive maxima ( pulses) increase in continuous manner, we can say that the path difference (x) or phase difference varies in continuous manner.
(iii) We are using monochromatic light in YDSE to avoid overlapping and to have very clear pattern on the screen.