Polarization

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JEE Advanced 2026

LEVELJEE Advanced

As shown in the figure, a ray $A B$ of unpolarized light enters from water of refractive index $n_{w} = 4/3$ into a medium of refractive index $n_{p} = 4/ 3$ after passing through a glass plate of refractive index $n_{g} = 1.5$ and a layer of water. At a particular incident angle $i$ the reflected ray $C D$ is polarized in the direction as shown in the figure. The value of $i$ (in degrees) is:

JEE Main 2024

LEVELJEE Main

A point source S emits unpolarized light uniformly in all directions. At two points A and B, the ratio $r = I_{A} / I_{B}$ of the intensities of light is 2. If a set of two polaroids having $4 5^{\circ}$ angle between their pass-axes is placed just before point B, then the new value of r will be _____.

JEE Main 2026

LEVELJEE Main

In the List-I, four optical effects are mentioned. The physical phenomena of light which are essential to describe these optical effects are given in List-II. Choose the option which describes the correct match between the entries in List-I to those in List-II.

List-I

(P)

Colorful sky in north polar region (Aurora Borealis)

(Q)

Partially polarized sun light

(R)

Rainbow

(S)

Dark and bright fringes

List-II

(1)

Dispersion and reflection

(2)

Total internal reflection

(3)

Diffraction

(4)

Scattering of light by molecules in the atmosphere

(5)

Emission of radiation from oxygen and nitrogen atoms excited by charged particles

JEE Main 2025

LEVELJEE Advanced

A solid glass sphere of refractive index $n = 3$ and radius $R$ contains a spherical air cavity of radius $\frac{R}{2}$ , as shown in the figure. A very thin glass layer is present at the point O so that the air cavity (refractive index $n = 1$ ) remains inside the glass sphere. An unpolarized, unidirectional and monochromatic light source $S$ emits a light ray from a point inside the glass sphere towards the periphery of the glass sphere. If the light is reflected from the point O and is fully polarized, then the angle of incidence at the inner surface of the glass sphere is $θ$ . The value of $sin θ$ is ____

JEE Main 2014

LEVELJEE Main

Two beams, $A$ and $B$ , of plane polarised light with mutually perpendicular planes of polarisation are seen through a polaroid. From the position, when the beam $A$ has maximum intensity (and beam $B$ has zero intensity), a rotation of polaroid through $3 0^{\circ}$ makes the two beams appear equally bright. If the initial intensities of the two beams are $I_{A}$ and $I_{B}$ respectively, then $I_{A} / I_{B}$ equals

The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index $n$ ), is

(A)

sin^{- 1} (n)

(B)

sin^{- 1} (\frac{1}{n})

(C)

tan^{- 1} (\frac{1}{n})

(D)

tan^{- 1} (n)

JEE Main 2013

LEVELJEE Main

A beam of unpolarised light of intensity $I_{0}$ is passed through a polaroid $A$ and then through another polaroid $B$ which is oriented so that its principal plane makes an angle of $4 5^{\circ}$ relative to that of $A$ . The intensity of the emergent light is

(A)

I_{0}

(B)

\frac{I _{0}}{2}

(C)

\frac{I _{0}}{4}

(D)

\frac{I _{0}}{8}

JEE Main 2021

LEVELJEE Main

An unpolarised light beam is incident on the polariser of a polarisation experiment and the intensity of light beam emerging from the analyser is measured as $100$ lumens. Now, if the analyser is rotated around the horizontal axis (direction of light) by $3 0^{\circ}$ in clockwise direction, the intensity of emerging light will be ....... lumens.

JEE Main 2021

LEVELJEE Main

A source of light is placed in front of a screen. Intensity of light on the screen is $I$ . Two polaroids $P_{1}$ and $P_{2}$ are so placed in between the source of light and screen that the intensity of light on screen is $I /2$ . $P_{2}$ should be rotated by an angle of ........... (degrees), so that the intensity of light on the screen becomes $3 I /8$ .

JEE Main 2020

LEVELJEE Advanced

A polariser-analyser set is adjusted such that the intensity of light coming out of the analyser is just 10% of the original intensity. Assuming that the polariser-analyser set does not absorb any light, the angle by which the analyser need to be rotated further to reduce the output intensity to be zero, is

(A)

71. 6^{\circ}

(B)

9 0^{\circ}

(C)

4 5^{\circ}

(D)

18. 4^{\circ}

LEVELJEE Main

Statement I: On viewing the clear, blue portion of the sky through a Calcite crystal, the intensity of transmitted light varies as the crystal is rotated. Statement II: The light coming from the sky is polarised due to scattering of sun light by particles in the atmosphere. The scattering is largest for blue light.

(A)

Statement I is false, Statement II is true

(B)

Statement I is true, Statement II is false

(C)

Statement I is true, Statement II is true; Statement II is the correct explanation of Statement I

(D)

Statement I is true, Statement II is true; Statement II is not the correct explanation of Statement I

JEE Main 2019

LEVELJEE Main

A system of three polarisers $P_{1}, P_{2}, P_{3}$ is set up such that the pass axis of $P_{3}$ is crossed with respect to that of $P_{1}$ . The pass axis of $P_{2}$ is inclined at $6 0^{\circ}$ to the pass axis of $P_{3}$ . When a beam of unpolarised light of intensity $I_{0}$ is incident on $P_{1}$ , the intensity of light transmitted by the three polarisers is $I$ . The ratio $(I_{0} / I)$ equals (nearly)

A beam of plane polarised light of large cross-sectional area and uniform intensity of $3.3 Wm^{- 2}$ falls normally on a polariser, which rotates about its axis with an angular speed of $31.4 rad/s$ . The energy of light passing through the polariser per revolution is close to (Take, cross-sectional area $= 3 \times 1 0^{- 4} m^{2}$ )

(A)

1.5 \times 1 0^{- 4} J

(B)

5.0 \times 1 0^{- 4} J

(C)

1.0 \times 1 0^{- 4} J

(D)

1.0 \times 1 0^{- 5} J

JEE Main 2019

LEVELJEE Advanced

Consider a tank made of glass (refractive index is $1.5$ ) with a thick bottom. It is filled with a liquid of refractive index $μ$ . A student finds that, irrespective of what the incident angle $i$ (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarised. For this to happen, the minimum value of $μ$ is

(A)

\frac{3}{5}

(B)

\frac{5}{3}

(C)

\frac{4}{3}

(D)

\frac{5}{3}

LEVELBoard

When an unpolarised light of intensity $I_{0}$ is incident on a polarising sheet, the intensity of the light which does not get transmitted is

(A)

\frac{1}{2} I_{0}

(B)

\frac{1}{4} I_{0}

(C)

zero

(D)

I_{0}

JEE Main 2018

LEVELJEE Main

Unpolarised 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 $\frac{I}{2}$ . Now, another identical polariser $C$ is placed between $A$ and $B$ . The intensity beyond $B$ is now found to be $\frac{I}{8}$ . The angle between polariser $A$ and $C$ is

(A)

0^{\circ}

(B)

3 0^{\circ}

(C)

4 5^{\circ}

(D)

6 0^{\circ}

In the List-I, four optical effects are mentioned. The physical phenomena of light which are essential to describe these optical effects are given in List-II. Choose the option which describes the correct match between the entries in List-I to those in List-II.

List-I

List-II

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index n), is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } When an unpolarised light of intensity I0​ is incident on a polarising sheet, the intensity of the light which does not get transmitted is

The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index $n$ ), is

When an unpolarised light of intensity $I_{0}$ is incident on a polarising sheet, the intensity of the light which does not get transmitted is