In Young's double slit experiment of central fringe is $I_0$ and fringe width is $\beta$. If a point is at a…
In Young's double slit experiment of central fringe is $I_0$ and fringe width is $\beta$. If a point is at a distance $x$ from the central fringe, then the intensity at that point is
Intensity at distance $x$ from central maximum is given by
$
I=4 I_0 \cos ^2 \frac{\phi}{2}
$
where, $\phi=\frac{2 \pi d}{\lambda} \sin \theta$
Also, $\quad \beta=\frac{\lambda D}{d}$
Combining these, we get
$
I=I_0 \cos ^2\left(\frac{\pi x}{\beta}\right)
$
