Light waves from two coherent sources arrive at two points on a screen with path difference of zero and…
Light waves from two coherent sources arrive at two points on a screen with path difference of zero and $\lambda / 2$. The ratio of the intensities at the points is
two : one
one:two
one: one
infinity: one
Solution
When path difference is zero, the resultant intensity $I=4 I_{0}$, where $I_{0}$ is the intensity of the individual waves.
When the path difference is $\frac{\lambda}{2}$, the intensity $I^{\prime}=0$
$\therefore \frac{I}{I^{\prime}}=\frac{4 I_{0}}{0}=\infty$