At the end of Example 27.8, it was stated that the intensity of polarized light is reduced to 90.0% of its original value by passing through a polarizing filter with its axis at an angle of 18.4° to the direction of polarization. Verify this statement.

Data from Example 27.8

What angle is needed between the direction of polarized light and the axis of a polarizing filter to reduce its intensity by 90%?
Strategy

When the intensity is reduced by 90.0%, it is 10.0% or 0.100 times its original value. That is, I = 0.100I₀. Using this information, the equation I = I₀ cos² θ can be used to solve for the needed angle.