Give the uses of Polaroids.

Question 170 of 199

Q. Give the uses of Polaroids.

Tamil Nadu DgeTamil Nadu HSC (DGE) Board 2022Subjective· 3mImportance★★★★★

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Polaroids are used wherever selectively blocking one polarisation of light is useful: reducing glare, 3D imaging, LCDs, and analysing stress in transparent materials.

Anti-glare applications: Polaroid sunglasses and Polaroid window panes cut down the intensity of glare from reflected/scattered light (which is often partially polarised) without blocking all light, improving visual comfort. Similarly used in car windscreens/headlights to reduce glare from oncoming traffic.
Photography and cinema: Polaroid filters on camera lenses reduce unwanted reflections and enhance colour/contrast in photographs; pairs of differently oriented Polaroid glasses are used to view 3D movies, each eye receiving only the differently-polarised image intended for it.
Photoelasticity (stress analysis): Polaroids are used to study the stress distribution in transparent engineering materials/models — when placed under stress and viewed between crossed Polaroids, the model shows characteristic coloured fringe patterns revealing regions of high stress. …

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Same / Similar Concept — real previous-year questions on the same or a closely similar concept, not this exact question.

Showing the 12 most recent of 20 on this concept.

CBSE 2026Set A1 markMCQ
$Q. Natural light from the sun is (A) polarised (B) unpolarised (C) partially polarised (D) linearly polarised$
›Reveal solutionSolution

Natural sunlight vibrates equally in all planes perpendicular to its direction of travel, so it is unpolarised.

Light is a transverse electromagnetic wave, so its electric field oscillates in the plane perpendicular to the direction of propagation. In light from the Sun the emission comes from countless independent atoms, each radiating with a random orientation of the electric vector. Averaged over these, there is no preferre …

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CBSE 2025Set X11 mark
$Q. Polarization of light shows that light is a ________ wave.$
›Reveal solutionSolution

transverse Only transverse waves, whose vibrations are perpendicular to the direction of propagation, can be polarized. The fact that light can be polarized proves that light is a transverse w …

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CBSE 2025Set D1 markMCQ
$Q. In polarised light the angle between plane of vibration and plane of polarization is (A) 0° (B) 45° (C) 90° (D) 180°$
›Reveal solutionSolution

By definition the plane of polarization is at right angles to the plane of vibration, so the angle is 90°.

In polarised light the electric-field vector vibrates in one plane, called the plane of vibration. The plane of polarization is conventionally defined as the plane perpendicular to the plane of vibration (containing the directio …

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CBSE 2025Set D1 markMCQ
$Q. Which of the following cannot be polarized? (A) Sound waves (B) Light waves (C) Radio waves (D) X-rays$
›Reveal solutionSolution

Only transverse waves can be polarized; sound in air is longitudinal, so it cannot be polarized.

Polarization requires the vibrations to be perpendicular to the direction of propagation, i.e. the wave must be transverse. Light waves, radio waves and X-rays are all electromagnetic (transverse) waves and can be polarized.

…

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CBSE 2025Set A1 mark
$Q. Write True or False: For an unpolarised wave the displacement remains constant with respect to time.$
›Reveal solutionSolution

The statement is False: unpolarised light has a rapidly and randomly varying direction of vibration, not a constant one.

Ordinary (unpolarised) light consists of a large number of wave trains emitted by different atoms, each vibrating in its own transverse plane. The resultant electric field vector's direction of vibration therefore changes randomly and rapidly with time, and on average is symmetric about the direction of propagation — this is precisely why it is called 'unpolarised'. In contrast, a polarised wave has its vi …

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CBSE 2025Set ANNUAL1 markMCQ
$Q. The confirmation of transverse nature of light waves is by$
(a) reflection
(b) refraction
(c) polarisation
(d) interference
›Reveal solutionSolution

Polarisation restricts vibrations to a single plane, which is only possible for a transverse wave; longitudinal waves cannot be polarised at all — so the fact that light CAN be polarised proves it is transverse.

Reflection, refraction, and interference occur for both transverse and longitudinal waves (e.g. sound, a longitudinal wave, also reflects, refracts, and interferes), so these phenomena alone cannot distinguish the two. Polarisation, however, is possible only for transverse waves, since it involves restricting the oscillation direction (which is …

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CBSE 2025Set ANNUAL1 markMCQ
$Q. The transverse nature of light is shown in :$
(a) scattering
(b) interference
(c) polarisation
(d) diffraction
›Reveal solutionSolution

Polarisation is possible only for transverse waves, so light's ability to be polarised demonstrates its transverse character.

Working

Scattering, interference and diffraction occur for both transverse and longitudinal waves, so they do not by themselves reveal a wave's transverse nature. Polarisation, however, involves restricting oscillation to a single plane perpendicular to the direction of travel -- something only a transverse wave's oscillating field can undergo. That light can be polarised …

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CBSE 2024Set ANNUAL1 markMCQ
$Q. Natural light from the sun is -$
(a) polarised
(b) unpolarised
(c) partially polarised
(d) linear polarised
›Reveal solutionSolution

Ordinary light from the sun consists of a huge number of independent wave trains vibrating randomly in every direction perpendicular to the direction of travel, so it is unpolarised.

Light is a transverse wave, so its electric field vibrates in a plane perpendicular to the direction of propagation. In light emitted directly by a natural source like the sun, this vibration direction changes randomly and rapidly, with no preferred plane — such light is called unpolarised.

…

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CBSE 2024Set ANNUAL1 markMCQ
$Q. The transverse nature of light is shown in :$
(a) scattering
(b) interference
(c) polarisation
(d) diffraction
›Reveal solutionSolution

Polarisation is a property unique to transverse waves, so the fact that light can be polarised is direct evidence of its transverse nature.

Working

Scattering, interference and diffraction are exhibited by both transverse and longitudinal waves (e.g. sound, a longitudinal wave, also shows interference and diffraction), so these phenomena alone do not distinguish a transverse wave from a longitudinal one.

…

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CBSE 2023Set F1 markMCQ
$Q.Light is a transverse wave because it shows (A) Reflection (B) Polarization (C) Interference (D) Diffraction$
›Reveal solutionSolution

Polarization is possible only for transverse waves ⇒ it proves light is transverse.

Reflection, interference and diffraction are shown by BOTH longitudinal and transverse waves, so they cannot distinguish the two. Polarization — restricting the vibrations to a single plane — is possible only when the oscillations are perpendicular to t …

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CBSE 2023Set F1 markMCQ
$Q. Which is used to produce polarised light? (A) Prism of flint glass (B) NaCl prism (C) Nicol prism (D) Biprism$
›Reveal solutionSolution

A Nicol prism produces plane-polarised light.

A Nicol prism is made from a calcite crystal cut and cemented with Canada balsam. Inside the crystal an unpolarised beam splits into two plane-polarised rays (ordinary and extraordinary) by double refraction. The ordinary ray undergoes total internal reflection at the balsam layer and is absorbed, while the extraordinary ray passe …

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CBSE 2022Set ANNUAL1 mark
$Q. Light waves are ____ in nature. (transverse, longitudinal)$
›Reveal solutionSolution

Light is a transverse wave — its electric and magnetic field oscillations are perpendicular to the direction of propagation.

In a transverse wave, the disturbance (here, the oscillating electric and magnetic fields) is perpendicular to the direction the wave travels; in a longitudinal wave, the disturbance is along the direction of travel (like sound). Light, being an electromagnetic wave, has its E and B fields oscillating perpendicular to each other and to the direction of propagation, which makes it transverse. This transverse nature is confirmed experimentally by …

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Q.Give the uses of Polaroids.

Concept understanding — Plane Polarised Light and Polarisation Techniques

Q.Give the uses of Polaroids.

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