Question

Light that passes through a series of three polarizing filters emerges from the third filter horizontally polarized with an intensity of 280 W/m2. 1) If the polarization angle between the filters increases by 25∘ from one filter to the next, find the intensity of the incident beam of light, assuming it is initially unpolarized. (Express your answer to two significant figures.

Answer 1

Answer:

8.3×10² W/m²

Explanation:

I₀ = Intensity of unpolarized light

θ = angle between the filters = 25°

I = Intensity of the polarized light after passing through three filters = 280 W/m²

$I=\frac{I_0}{2}cos^2{25}cos^2{25}\\\Rightarrrow I_0=\frac{2I}{cos^4{25}}\\\Rightarrow I_0=\frac{2\times 280}{cos^4{25}}\\\Rightarrow I_0=830.01\ W/m^2$

∴ Intensity of unpolarized light is 8.3×10² W/m²