Optics
Malus's Law
The intensity of polarized light after passing through a polarizer at angle θ.
Variables
IW/m²
Transmitted intensity
Allowed values: 0 or more
I0W/m²
Initial intensity
Allowed values: greater than 0
θ°
Angle between polarizer and light polarization
Your notes
0/5000
Check value
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- I0 = 2 W/m² (Initial intensity)
- θ = 3 ° (Angle between polarizer and light polarization)
Result: I = 1.9945219 W/m²
Where this formula is listed
- Optics formulas, under Polarization.
- In the optics list it comes after Brewster's Angle and before Rayleigh Criterion.
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Malus's Law formula?
Malus's Law is written I = I₀ cos² θ. The intensity of polarized light after passing through a polarizer at angle θ. It belongs to Optics, under Polarization.
What are the units in I = I₀ cos² θ?
In SI units, I is transmitted intensity, measured in W/m²; I₀ is initial intensity, measured in W/m²; θ is angle between polarizer and light polarization, measured in °.