Question

If we observe the single slit Fraunhofer diffraction with wavelength $\lambda$ and slit width $d$, the width of the central maxima is $2 \theta$. On decreasing the slit width for the same $\lambda$

• A. $\theta$ increases
• B. $\theta$ remains unchanged
• C. $\theta$ decreases
• D. $\theta$ increases or decreases depending on the intensity of light

Answer 1

Answer: (A)

$2 \theta=\frac{2 \lambda}{d}$ (where $d=$ slit width
As $d$ decreases, $\theta$ increases.