Question

a polarized beam of light emerging from a single polarizer has an intensity of 6000 w/m². if the beam of light incident on the polarizer was unpolarized, what was the intensity of the initial beam of light?
3000 w/m²
1500 w/m²
12000 w/m²
6000 w/m²

Explanation:

Step1: Apply Malus' law for unpolarized light

When unpolarized light passes through a polarizer, the intensity of the emerging polarized light \(I\) is related to the intensity of the incident unpolarized light \(I_0\) by the formula \(I=\frac{I_0}{2}\).

Step2: Solve for \(I_0\)

We know \(I = 6000\space W/m^2\). Rearranging the formula \(I=\frac{I_0}{2}\) for \(I_0\), we get \(I_0 = 2I\).
Substituting \(I = 6000\space W/m^2\) into the equation, we have \(I_0=2\times6000\space W/m^2\).

Answer:

\(12000\space W/m^2\) (the third option)