Physics - Wave Optics Question with Solution | TestHub

The correct option is (D) Concept: If $\mathrm{D}>>\mathrm{d}$, the linear width of the central principal maximum is equal to the product of angular width and the distance $D$. $\beta =\frac{2\lambda D}{d}$, where $d$ is the width of the slit. The linear width of the principal maximum will be equal to slit width for a value of $\mathrm{D}$ given by $\frac{2\lambda D}{d}=d$ or $\mathrm{D}=\frac{{\mathrm{d}}^2}{2\lambda }$