Enter the maximum intensity and the angle of incident intensity into the Calculator. The calculator will evaluate the Intensity from Malus Law. 

Intensity from Malus Law Formula

I = Imax * cos^2(a)


  • I is the Intensity from Malus Law ()
  • Imax is the maximum intensity
  • a is the angle of incident intensity

To calculate Intensity from Malus Law, multiply the maximum intensity by the cosine squared of the angle of incident.

How to Calculate Intensity from Malus Law?

The following steps outline how to calculate the Intensity from Malus Law.

  1. First, determine the maximum intensity. 
  2. Next, determine the angle of incident intensity. 
  3. Next, gather the formula from above = I = Imax * cos^2(a).
  4. Finally, calculate the Intensity from Malus Law.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

maximum intensity = 500

angle of incident intensity = 43