Basics of Polarization of Light

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Basics of Polarization of Light: Overview

This topic covers concepts such as Polarisation of Light Waves, Terms in Polarisation, Unpolarised Light Wave, Plane of Polarisation, and Plane of Vibration.

Important Questions on Basics of Polarization of Light

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Light, from a sodium lamp, is passed through two Polaroid sheets,   P 1  and   P 2  kept one after the other. Keeping   P 1  fixed,   P 2  is rotated so that its ‘pass – axis’ can be at different angles, θ  with respect to the pass – axis of P 1 .

An experimentalist records the following data for the intensity of light coming out of   P 2  as a function of the angle θ .

S. No. 

θ(Angle between the pass -axis of the two polaroids)

10° 230° 345° 460° 590°
I (Intensity of light coming out of P2) I02 38I0 122I0 I08 0


[ I 0  = Intensity of beam falling on   P 1 ]

One of these observations is not in agreement with the expected theoretical variation of I. Identify this observation.

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Two polaroids are set in crossed positions. A third polariser is placed between the two making an angle θ with the pass axis of the first polaroid. In what orientations(of third polaroid with respect to first polaroid) will the transmitted intensity be (i) minimum and (ii) maximum?

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Two rays of light A and B are falling on a glass slab at the angles of incidence 45° and 60°. If the reflected ray of A is partially polarized and that of B is completely polarized, then the refractive index of glass is

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Two polarisers are placed parallel to each other in the path of a beam of unpolarized light of intensity I0. The intensity of emergent beam is I02. If the first polariser is rotated about the line shown.

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A beam of laser light is incident on an analyzer which is rotated on a spectrometer stage. If the intensity of the transmitted light changes from maximum to minimum (not zero), the nature of the incident beam is

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A parallel beam of light, linearly polarized along the y-axis, passes through a combination of convex lenses and mirrors as shown in the figure. The output beam

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Unpolarized light having an intensity I0 passes through a stack of 4 polarizers, the pass axis of each of the polarizer makes an angle of 30° with the axis of the preceding one. The intensity of light coming out of the last polarizer is

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The refractive index of a certain medium (w.r.t. air) is n=3. Unpolarized light traveling from air to this medium is partially reflected and partially transmitted. At what angle of incidence would the reflected light be fully polarized?

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Two polarizers A and B are parallel to each other with the pass axis of B inclined at an angle of 30° to that of A. A linearly polarized light of intensity I0, having its direction of polarization at an angle θ with the pass axis of A, is incident normally on A and passes through B. If the intensity of light transmitted through B is 38I0, the angle θ is

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Unpolarized light is incident on the surface of a transparent medium at such an angle of incidence that the reflected ray and the refracted ray travel at right angles to each other.

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Assertion: The electromagnetic waves of all wavelengths can be polarise.

Reason: Polarization is independent of the wavelengths of electromagnetic waves.

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Unpolarized light of intensity I passes through an ideal polariser A. Another identical polariser B is placed behind A. The intensity of light beyond B is found to be I2. Now another identical polariser C is placed between A and B. The intensity beyond B is now found to be I8 . The angle between polariser A and C is

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If there is zero absorption in the polaroid and if the intensity of plane-polarized light coming out of polaroid is A2, then the intensity of the incident beam will be

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Waves which cannot be polarised are,

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An electromagnetic wave in vacuum has the electric and magnetic fields E and B which are always perpendicular to each other. The direction of polarizations is given by X and wave propagation by K then

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Which one of the following is an example of an unpolarised light?

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Sound wave are not polarized because:

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Calculate the amplitude of unpolarised light incident on the polariser if the amplitude of transmitted polarised light through it is A2.

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A beam of natural light falls on a system of 5 nicol prisms, whose transmission axis are turned, each through an angle α = 30o, with respect to the previous prism. The fraction of the intensity that passed through the system is

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Which of the following cannot be polarized?