aligned-second-polarizer-does-not-change-the-ledger - Electromagnetic Waves and Polarization Step by Step

An aligned second polarizer keeps intensity unchanged in the checked model. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

An aligned second polarizer does not reduce intensity

A second polarizer on the same axis has projection factor 1 and keeps the same value.

I_{\mathrm{in}}=25\ \text{W}/\text{m}^{2},\; I_{\mathrm{out}}=I_{\mathrm{in}}\cdot1=25\ \text{W}/\text{m}^{2}