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प्रश्न
Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why.
उत्तर
To show light waves are transverse in nature:
Take two polaroids T1 and T2 cut with their faces parallel to the axis of the crystal
When polaroid T1 is rotated about the direction of the propagation of light as axis, the intensity of the transmitted light remains the same. When T2 is rotated gradually, the intensity goes on decreasing and the transmitted light disappears completely when T2 is perpendicular to T1.
This happens because the polaroid allows only those vibrations of light which are parallel to its axis. This is true only if light has vibrations in all possible directions and hence is a transverse wave.
Light waves are transverse waves. So, they have electric vectors in all possible directions. When a polaroid is placed in between the path of the light, the electric vectors which are parallel to the pass-axis of the polaroid pass through it. Even if the polaroid is rotated, there would be other electric vectors which pass through it. So, the intensity of light does not change irrespective of the orientation of pass-axis of the polaroid.
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संबंधित प्रश्न
What is a Polaroid?
Show, with the help of a diagram, how unpolarised sunlight gets polarised due to scattering.
Show using a proper diagram how unpolarised light can be linearly polarised by reflection from a transparent glass surface.
What does a polaroid consist of? How does it produce a linearly polarised light?
A ray of ordinary light is travelling in air. It is incident on air glass pair at a polarising angle of 56°. Find the angle of refraction in glass.
Greenlight is an incident at the polarising angle on a certain transparent medium. The angle of refraction is 30°.
Find
(i) polarising angle, and
(ii) refractive index of the medium.
Mention the types of optically active crystals with example.
An unpolarised light of intensity 32 Wm-2 passes through three Polaroids such that the axes of the first and the last Polaroids are at 90°. What is the angle between the axes of the first and middle Polaroids so that the emerging light has an intensity of only 3 Wm-2?
The reflected light is found to be plane polarised when an unpolarized light falls on a denser medium at 60° with the normal. Find the angle of refraction and critical angle of incidence for total internal reflection in the denser to rarer medium reflection.
A plane mirror produces a magnification of
