Question

In a Young's double slit experiment, the intensities at two points, for the path respectively. If $I_0$ denotes the intensity produced by each one of the individual slits, then $\frac{I_1+I_2}{I_0}=$_______

Answer 1

$ I =4 I _0 \cos ^2\left(\frac{\Delta \phi}{2}\right)$
$ I _1=4 I _0 \cos ^2\left(\frac{\pi}{4}\right)=2 I _0$
$ I _2=4 I _0 \cos ^2\left(\frac{2 \pi}{3}\right)= I _0 $
$ \Rightarrow \frac{ I _1+ I _2}{ I _0}=3$