$A$ parallel beam of monochromatic light of wavelength $5000 \; \mathring{A}$ is incident normally on a single narrow slit of width $0.001 \; mm$. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to ........$^o$.

The phenomenon of diffraction was discovered by ...... .

Which of the following waves exhibits clear diffraction?

Light of wavelength $\lambda = 5000 \ \mathring{A}$ falls normally on a narrow slit. $A$ screen is placed at a distance of $1 \ m$ from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at $5 \ mm$ from the centre of the central maximum. The width of the slit is ....... $mm$.

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

$A$ linear aperture whose width is $0.02\, cm$ is placed immediately in front of a lens of focal length $60\, cm.$ The aperture is illuminated normally by a parallel beam of wavelength $5 \times 10^{-5}\, cm.$ The distance of the first dark band of the diffraction pattern from the centre of the screen is .....$cm$