
Two polaroid are oriented with their transmission axes making angle of \[30^{\circ}\] with each other. The fraction of incident unpolarised light is transmitted.
A. 37%
B. 37.5%
C. 3.36%
D. 33.6%
Answer
164.7k+ views
Hint:Light turns into linearly polarised light when it passes through a polaroid. According to the Law of Malus, the transmitted intensity is inversely proportional to the square of the amplitude (square of the cosine of the angle between the two polaroid). Malus's Law describes the relationship between polarised light transmission and incident intensity.
Formula used:
${I_t} = {I_0}{\cos ^2}\theta $
($\theta $is the angle created between the two Polaroid, ${I_t},{I_0}$are the intensities of the incident and transmitted light, respectively.)
Complete answer:

Also, the value of ${I_0} = \dfrac{{{I_i}}}{2}$
Before moving on to the calculating portion, let's talk about a few Polaroid facts.
In order to transmit light exclusively in one direction of the electric vector, Polaroid is made of a huge sheet of synthetic material densely packed with small crystals of a dichroic substance that are positioned parallel to one another.
When the angle is 30 degrees, we will now determine the value of the fraction.
According to the Malus's Law,
$ \Rightarrow {I_t} = {I_0}{\cos ^2}30$
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = \dfrac{1}{2} \times {(\dfrac{{\sqrt 3 }}{2})^2}$
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = \dfrac{3}{8}$
So converting into percentage we get,
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = 37.5\% $
So the correct option is B.
Note: Light typically scatters in all directions, but when it reflects from flat surfaces, it tends to become polarised. Polaroid is used in aeroplane glass windows to control light intensity, to view three-dimensional images and movies, as a filter in photographic cameras, to create plane polarised light, to enhance colour contrast in oil paintings, in calculators, and on LCD monitors in laptops
Formula used:
${I_t} = {I_0}{\cos ^2}\theta $
($\theta $is the angle created between the two Polaroid, ${I_t},{I_0}$are the intensities of the incident and transmitted light, respectively.)
Complete answer:

Also, the value of ${I_0} = \dfrac{{{I_i}}}{2}$
Before moving on to the calculating portion, let's talk about a few Polaroid facts.
In order to transmit light exclusively in one direction of the electric vector, Polaroid is made of a huge sheet of synthetic material densely packed with small crystals of a dichroic substance that are positioned parallel to one another.
When the angle is 30 degrees, we will now determine the value of the fraction.
According to the Malus's Law,
$ \Rightarrow {I_t} = {I_0}{\cos ^2}30$
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = \dfrac{1}{2} \times {(\dfrac{{\sqrt 3 }}{2})^2}$
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = \dfrac{3}{8}$
So converting into percentage we get,
$ \Rightarrow \dfrac{{{I_t}}}{{{I_i}}} = 37.5\% $
So the correct option is B.
Note: Light typically scatters in all directions, but when it reflects from flat surfaces, it tends to become polarised. Polaroid is used in aeroplane glass windows to control light intensity, to view three-dimensional images and movies, as a filter in photographic cameras, to create plane polarised light, to enhance colour contrast in oil paintings, in calculators, and on LCD monitors in laptops
Recently Updated Pages
Uniform Acceleration - Definition, Equation, Examples, and FAQs

JEE Main 2021 July 25 Shift 1 Question Paper with Answer Key

JEE Main 2021 July 22 Shift 2 Question Paper with Answer Key

JEE Atomic Structure and Chemical Bonding important Concepts and Tips

JEE Amino Acids and Peptides Important Concepts and Tips for Exam Preparation

JEE Electricity and Magnetism Important Concepts and Tips for Exam Preparation

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility, & More

Atomic Structure - Electrons, Protons, Neutrons and Atomic Models

JEE Main 2025: Derivation of Equation of Trajectory in Physics

Displacement-Time Graph and Velocity-Time Graph for JEE

Electric field due to uniformly charged sphere class 12 physics JEE_Main

Electric Field Due to Uniformly Charged Ring for JEE Main 2025 - Formula and Derivation

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

JEE Advanced Weightage 2025 Chapter-Wise for Physics, Maths and Chemistry

Degree of Dissociation and Its Formula With Solved Example for JEE

Wheatstone Bridge for JEE Main Physics 2025

Charging and Discharging of Capacitor

Instantaneous Velocity - Formula based Examples for JEE
