The figure shows two coherent sources $S_1$ and $S_2$ emitting waves of wavelength $\lambda$. The distance between the two sources is $3\lambda$. Find in terms of $\lambda$, the maximum distance from $S_1$ along $S_1 P$, for which destructive interference occurs 

Assuming the expression for the path difference between two waves meeting at a point on the screen, obtain an expression for the fringe width in Young’s double slit experiment.

When are two sources of light said to be coherent ?

The figure shows four pairs of polaroids, seen from the front. Each pair is mounted in the path of initially unpolarized light. The axis of polaroids is shown with dotted lines.Through which pair the intensity of light seen is maximum?

The figure shows four pairs of polaroids, seen from the front. Each pair is mounted in the path of initially unpolarized light. The axis of polaroids is shown with dotted lines.Through which pair the intensity of light seen is minimum?

 The figure shows two coherent sources $S_1$ and $S_2$ emitting waves of wavelength $\lambda$. The distance between the two sources is $3\lambda$. Find in terms of $\lambda$, the maximum distance from $S_1$ along $S_1 P$, for which destructive interference occurs