$A$ parallel monochromatic beam of light is incident normally on a narrow slit. $A$ diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first secondary maximum of the diffraction pattern,the phase difference between the rays coming from the edges of the slit is

Determine the angular separation between the central maximum and the first-order maxima of the diffraction pattern due to a single slit of width $0.25\, mm$ when light of wavelength $5890\,\mathring{A}$ is incident on it.

Light is incident normally on a diffraction grating through which the first order diffraction is seen at $32^\circ$. The second order diffraction will be seen at

To observe diffraction,the size of the obstacle

The box of a pinhole camera,of length $L$,has a hole of radius $a$. It is assumed that when the hole is illuminated by a parallel beam of light of wavelength $\lambda$,the spread of the spot (obtained on the opposite wall of the camera) is the sum of its geometrical spread and the spread due to diffraction. The spot would then have its minimum size (say $b_{min}$) when

Radio waves diffract around buildings,although light waves do not. The reason is that radio waves