In a diffraction pattern due to a single slit of width ‘a’, the first minimum is observed at an angle ${30^{\rm{o}}}$ when light of wavelength 5000 $\mathop {\rm{A}}\limits^{\rm{o}}$ is incident on the slit. The first secondary maximum is observed at an angle of:

Two coherent sources are 0.3 mm apart. They are 1 m away from the screen. The second dark fringe is at a distance of 0.3 cm from the centre. Distance of fourth bright fringe from the centre is

In the phenomenon of diffraction of light, when blue light is used in the experiment instead of red light, then

If ${{I_0}}$ is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit which is doubled

A single slit is located effectively at infinity in front of a lens of focal length $1\;{\rm{m}}$ and it is illuminated normally with light of wavelength $600\;{\rm{nm}}$. The first minima on either side of central maximum are separated by $4\;{\rm{mm}}$. Width of the slit is ……

A zone plate of focal length $60\;cm$, behaves as a convex lens, If wavelength of incident light is $6000\mathop {\rm A}\limits^ \circ$, then radius of first half period zone will be

A light wave is incident normally over a slit of width $24 imes {10^{ - 5}}\;cm$. The angular position of second dark fringe from the central maxima is $30^\circ$. What is the wavelength of light

A linear aperture of width 0.01 cm is placed in front of a lens of focal length 50 cm. The aperture is illuminated normally by a parallel beam of wavelength $5 imes 10^{-5}$ cm. What is the distance of the first dark band of the diffraction pattern from the centre of the screen?

A single slit of width $d$ is illuminated by violet light of wavelength $400\;nm$ and the width of the diffraction patter is measured as $y$. When half of the slit width is covered and illuminated by yellow light of wavelength $600\;nm$ , the width of the diffraction pattern is

A narrow stream of electrons of energy 100eV is fired at two parallel slits very close to each other. The distance between the slits is 10A. The electron waves after passing through the slits interfere on a screen, 3m away from slits. The fringe width is

What is the effect on Fresnel’s biprism experiment when the use of white light is made