malus-law-squares-the-projection - Electromagnetic Waves and Polarization Step by Step

A polarizer transmits intensity as the squared projection factor. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Malus law squares the projection factor

For one polarizer, transmitted intensity is the source intensity times the squared projection factor.

I_{\mathrm{out}}=I_{\mathrm{in}}\cdot\left(\frac{3}{5}\right)^{2}= 9\ \text{W}/\text{m}^{2}, 16\ \text{W}/\text{m}^{2}