cbse-2020

Show using a proper diagram how unpolarized light can be linearly polarised by reflection from a transparent glass surface.

If one of two identical slits producing interference in Young’s experiment is covered with glass, so that the light intensity passing through it is reduced to $50\%$, find the ratio of the maximum and minimum intensity of the fringe in the interference pattern.

What kind of fringes do you expect to observe if white light is used instead of monochromatic light?

Define the term wavefront. Using Huygen$\text{'}$s wave theory, verify the law of reflection.

Define the term $"$refractive index$"$ of a medium. Verify Snell$\text{'}$s law of refraction when a plane wavefront is propagating from a denser to a rarer medium.

 Describe any two characteristic features which distinguish between interference and diffraction phenomena. Derive the expression for the intensity at a point of the interference pattern in Young’s double slit experiment.

In the diffraction due to a single slit experiment, the aperture of the slit is $3 mm$. If monochromatic light of wavelength $620 nm$ is incident normally on the slit, calculate the separation between the first order minima and the $3rd$ order maxima on one side of the screen. The distance between the slit and the screen is $1.5 m$.

Define wavefront of a travelling wave. Using Huygens principle, obtain the law of refraction at a plane interface when light passes from a denser to rarer medium.