Created By : Naaz Fatima

Reviewed By : Phani Ponnapalli

Last Updated : May 18, 2023

You may examine the malus intensity of light polarisation using this best Malus Law Calculator in a fraction of a second,. Simply enter the starting intensity and angle of incidence parameters into the free calculator tool's calculate button to get the result quickly and effortlessly.

Choose a Calculation
Initial Intensity:
Angle Of Incidence:

How to Determine Polarized Light Intensity?

To determine the intensity of polarised light, use the easy techniques outlined below.

  • Get the initial intensity of the incident light, as well as the angle between the polarizer's axis and the polarisation of the light.
  • The peak wavelength is multiplied by the Wien's displacement constant.
  • To check polarised light intensity, multiply the initial intensity by the square value.

For more concepts check out to get quick answers by using this free tool.

Malus Law Formula

According to Malus Law, the intensity of polarised light passing through an analyzer varies as the square of the cosine of the angle between the polarizer and the analyzer's transmission axes. This law can be used to quantitatively verify polarised light.

The formula for the Malcus law is as follows:

intensity = initial_intensity*cos2θ

  • Here, The output irradiance is measured in intensity.
  • The irradiance of incident light is the Initial intensity.
  • θ is the angle formed by the polarisation of light and the polarizer's axis.

What is the Purpose of a Polarizer?

A polarizer is a device that enables only one direction of light to travel through it. These are made up of molecules that are oblong in shape and oriented in the same direction. When the incident beam's polarisation is aligned in the same orientation as the incident beam, light is most likely to be absorbed. The polarisation is transmitted when it is perpendicular to the long axis, and the polarizer's axis is the direction. When the polarisation angle is in the middle, it passes through partially and its original intensity falls.

Malus Law Example

Question 1: The transmission axes of two polaroids A and B are kept at angle of 45° to one another. Find the transmitted light intensity if the light intensity incident on the system is 5W/m2.


Consider the problem, we have

Initial_intensity=4 W/m2

Angle θ=45°

Malus Law formula is intensity = initial_intensity*cos2θ



Intensity= 4*(0.525)2

Intensity= 4*0.276

Intensity= 1.102

As a result,The transmitted intensity of light is 1.102 W/m2

FAQs on Malus Law Calculator

1. What are some examples of polarised light's applications?

Polarized light is employed in a variety of applications, including eyeglass glare reduction, infrared spectroscopy, earthquake analysis, and differentiating between transverse and longitudinal waves.

2. What is the Malus law formula?

The polarisation qualities of light are dealt with by the malus law. It aids in comprehending the relationship between the polarizer analyzer and the intensity of light.The intensity of polarised light is calculated using the malus law formula: intensity = initial intensity*cos2θ.

3. What is polarisation of light?

Light is an electromagnetic wave that has both electric and magnetic fields that oscillate. It is linearly polarised if the orientation of the light oscillations is constant. Polarization by transmission, polarisation by scattering, polarisation by reflection, and polarisation by refraction are the several methods used to polarise light.

4. In Malus Law, what is the analyser?

The polarizer polarises light that passes through it. When light strikes another polaroid, the analyzer, it transmits light in accordance with the polarizer's axis orientation. Malus law determines the amount of light that passes through the analyser.