- A beam of light of wavelength $\lambda$ is incident normally on a single slit of width d. The angular width of the central maximum on a screen at a distance D from the slit is * 2$\lambda$/d * $\lambda$/d * $\lambda$/D * 2$\lambda$/D (2019)
The correct answer is 2$\lambda$/d.
The angular width of the central maximum is given by
$$\theta = \frac{2\lambda}{d}$$
where $\lambda$ is the wavelength of the light and $d$ is the width of the slit.
