Задача 40898.

The intensity of the natural light transmitted through a polaroid, decreased by 4.5 times. How many times it will decrease if the second supply is the same for the first polaroid so that the angle between the planes of polarization was 50 °? The absorption coefficient of light in both polaroids same.

Detailed solution with a short recording conditions, laws and formulas used in the decision, the withdrawal of the calculation formula and the answer.
If you have any questions about the decision to write. I try to help.