Physics - Wave Optics Question with Solution | TestHub

In Young's double slit experiment, the fringe width $X$ is given by the formula:

$X=\frac{\lambda D}{d}$

where:
$\lambda$ = wavelength of light used
$D$ = distance of the screen from the plane of the slits
$d$ = distance between the slits

The given graph is a straight line passing through the origin, plotted with $X$ on the y-axis and $D$ on the x-axis. The equation of this line can be written as:

$X=\left(\frac{\lambda }{d}\right)D$

Comparing this with the standard equation of a straight line $y=mx$, the slope of the graph is:

$\text{slope}=\frac{\lambda }{d}$

Rearranging the above equation to solve for the wavelength $\lambda$, we get:

$\lambda =\text{slope}\times d$

Answer: slope $\times d$