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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.
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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 dose a polaroid consist of?
Two polaroids P1 and P2 are placed with their pass axes perpendicular to each other. Unpolarised light of intensity I0 is incident on P1. A third polaroid P3 is kept in between P1 and P2 such that its pass axis makes an angle of 60° with that of P1. Determine the intensity of light transmitted through P1, P2 and P3.
A ray of light passes from a vacuum to a medium of refractive index (μ). The angle of
incidence is found to be twice the angle of refraction. The angle of incidence is _______.
A) `cos^(-1)(mu/2)`
B) cos−1(μ)
C) `2 cos^(-1) (mu/2)`
D) `2 sin^(-1) (mu/2)`
State two uses of Polaroid.
Explain how an unpolarised light gets polarised when incident on the interface separating the two transparent media.
Light transmitted by Nicol prism is ______.
What is plane polarised light?
Mention the types of optically active crystals with example.
What is normal focusing?
The intensity of transmitted light when a polaroid sheet, placed between two crossed polaroids at 22.5° from the polarization axis of one of the polaroids, is (I0 is the intensity or polarised light after passing through the first polaroid):
