Monochromatic light of wavelength $580 \,nm$ is incident on a slit of width $0.30 \,mm$. The screen is $2 \,m$ from the slit. The width of the central maximum is ........... $\times 10^{-3} \,m$.

In a single slit diffraction of light of wavelength $\lambda$ by a slit of width $e$,the size of the central maximum on a screen at a distance $b$ is

$A$ diffraction pattern is formed by blue light. If the blue light is replaced by yellow light, then . . . . . . .

$A$ monochromatic light of wavelength $6000 \text{ Å}$ is incident on a single slit of width $0.01 \text{ mm}$. If the diffraction pattern is formed at the focus of a convex lens of focal length $20 \text{ cm}$, the linear width of the central maximum is: (in $\text{ mm}$)

In deriving the single slit diffraction pattern,it is stated that the intensity is zero at angles of $\theta = n\lambda / a$,where $a$ is the slit width. Justify this by suitably dividing the slit to bring out the cancellation.

Red light of wavelength $625 \, nm$ is incident normally on an optical diffraction grating with $2 \times 10^{5} \, \text{lines}/m$. Including the central principal maxima, how many maxima may be observed on a screen which is far from the grating?