A linear aperture whose width is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aparture 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

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

The intensity at the maximum in a Young's double slit experiment is $$I$$₀. Distance between two slits is d = 5$$\lambda $$, where $$\lambda $$ is the wavelength of light used in the expreriment. What will be the intensity in front of one of the slits on the screen placed at a distance D = 10d ?

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern, the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is