ONE FORMULA, ONE ANSWER
Malus Law Transmitted Intensity Calculator
Calculate the intensity of linearly polarized light after an ideal analyzer. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Transmitted intensity I
Enter values and select Calculate.
I = I₀ cos² θ
Assumptions
Required: I₀≥0 and 0≤θ≤π/2. I₀ is the already linearly polarized intensity immediately before the analyzer. The one-half factor for initially unpolarized light is not applied automatically. The analyzer is ideal. Excluded: finite extinction ratio, additional absorption and reflection. Orthogonal axes give exactly zero.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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