In a single slit diffraction, the slit is illuminated with light of wavelength $6000 \text{ Å}$. If the slit were illuminated by a light of wavelength $\lambda$ the angular width of the central maximum decreases by $30 \%$. Then $\lambda$ is (in $\text{ Å}$)

Define diffraction.

$A$ Fraunhofer diffraction pattern due to a single slit of width $0.3 \text{ mm}$ is obtained on a screen placed at a distance of $3 \text{ m}$ from the slit. The first minima lie at $5.5 \text{ mm}$ on either side of the central maximum on the screen. The wavelength of light used is (in $\text{ Å}$)

The diffraction effect can be observed in

$A$ slit of width $d$ is illuminated by light of wavelength $\lambda$. The angular width of the central maximum is:

$A$ plane wave front of wavelength $\lambda$ is incident on a single slit of width $b$. What is the angular width of the secondary maximum?