Created By : Naaz Fatima

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 19, 2023

You can use this best Malus Law Calculator to check the malus intensity of light polarization within a fraction of seconds. Just enter the initial intensity and angle of incidence details and press on the calculate button of the free calculator tool to obtain the result easily and quickly.

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Initial Intensity:
Angle Of Incidence:

Steps to Find Intensity of Polarized Light

Follow the simple steps mentioned below to find the intensity of polarized light.

  • Get the initial intensity of the incident light, angle between the axis of polarizer and light polarization.
  • Compute the cos function of the angle and square the result.
  • Multiply the initial intensity by the square value to check polarized light intensity.

Malus Law Formula

Malus Law states that the intensity of the polarized light that passes through an analyzer differs as the square of the cosine of the angle between the polarizer and the transmission axes of the analyzer. This law is useful for the quantitative verification of polarized light.

The malcus law formula is given below:

intensity = initial_intensity * cos┬▓╬╕


intensity is the output irradiance

initial_intensity is the irradiance of incident light

╬╕ is the angle between the light polarization and the axis of the polarizer

How a Polarizer Work?

The polarizer is a device that allows light to pass only in a certain direction. These are made up of oblong-shaped molecules aligned in the same direction. When the polarization of the incident beam is in the same alignment of orientation, then light is most likely to be absorbed. When the polarization is perpendicular to the long axis, then it is transmitted and direction is the axis of the polarizer. If the angle of polarization is in between, it passes partially and its initial intensity decreases.


Question: Two polaroids A and B are kept with their transmission axes at an angle of 30 degrees with respect to other. If the intensity of the light incident on the system is 5 W/m┬▓, find the transmitted intensity of light?


Given that

Initial_intensity = 5 W/m┬▓

╬╕ = 30 degrees

Malus Law formula is intensity = initial_intensity * cos┬▓╬╕

intensity = 5 * cos┬▓(30┬░)

= 5 * (0.154)┬▓

= 5 * 0.0237

= 0.11

Therefore, the transmitted intensity of light is 0.11 W/m┬▓.

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Frequently Asked Questions on Acceleration Calculator

1. What are the applications of Polarized Light?

The applications of polarized light are used in sunglasses to reduce glare, infrared spectroscopy, seismology to study earthquakes, to differentiate between transverse and longitudinal waves, and so on.

2. What is the formula for Malus law?

The malus law deals with the polarization properties of light. It helps to understand the relation between the polarizer analyzer and light intensity. The malus law formula to calculate the intensity of the polarized light is intensity = initial_intensity * cos┬▓╬╕.

3. What is light polarization?

Light is an electromagnetic wave with oscillating electric and magnetic fields. If the orientation of the light oscillations is constant, then it is linearly polarized. The different methods used to polarize light is polarization by transmission, polarization by scattering, polarization by reflection, polarization by refraction.

4. What is the analyser in Malus Law?

When light falls on the polarizer, it gets polarized. If the light falls on another polaroid which is the analyzer, then it transmits light as per the orientation of the axis with the polarizer. The light intensity transmits through the analyzer is given by Malus law.