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?

In a diffraction pattern due to a single slit of width $a$,the first minimum is observed at an angle $30^{\circ}$ when light of wavelength $5000 \; \mathring{A}$ is incident on the slit. The first secondary maximum is observed at an angle of

The diffraction fringes obtained from a single slit are.....

$A$ screen is placed $0.5 \,m$ away from a single slit which is illuminated by a monochromatic light of wavelength $6000 \text{ Å}$. If the distance between the first and third minima in the diffraction pattern on the screen is $3 \,mm$, then the slit width is: (in $\,mm$)

The angular spread of the central maximum in a diffraction pattern does not depend on . . . . . . .

$A$ light source with a wavelength of $5000 \, \mathring A$ produces a single-slit diffraction pattern. The first minimum in the diffraction pattern is observed at a distance of $5 \, mm$ from the central maximum. The distance between the slit and the screen is $2 \, m$. Find the width of the slit. (in $, mm$)