Question

If $I_0$ is the intensity of the principle maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled ?

• A. $2I_0$
• B. $4I_0$
• C. $I_0$
• D. $\frac{I_0}{2}$

Answer 1

The correct option is B $4I_0$

Intensity of principle maxima is directly proportional to square of slit width.
$I\propto w^2$
$\frac{I^{{}^{\prime }}}{I_0}$ = ${\left(\frac{w^{{}^{\prime }}}{w}\right)}^2$
$\frac{I^{{}^{\prime }}}{I_0}$ = ${\left(\frac{2w}{w}\right)}^2$
$I^{{}^{\prime }}=4I_0$