Final answer:
To reduce the intensity of unpolarized light to 1/6, a polarizing filter needs to be placed at an angle where the cosine squared of that angle equals 1/6. Malus's Law is used for this calculation, and the angle needed is greater than 45° but less than 90°.
Step-by-step explanation:
The question pertains to the Malus's Law, which describes how the intensity of polarized light decreases as it passes through a polarizing filter at a certain angle. According to Malus's Law, the intensity I of polarized light after passing through a polarizing filter is I = I0 cos2(θ), where I0 is the initial intensity and θ is the angle between the light's initial polarization direction and the axis of the filter. To reduce the intensity of incident unpolarized light to 1/6 of its original value, or approximately 16.7%, we require the filter to make an angle with the polarization direction such that cos2(θ) = 1/6. Solving for θ, we would know the required angle.
As per the provided information and the fact that 45° reduces the intensity to 50%, we can infer that a larger angle is required to reduce it further to 16.7%. To find the exact angle, a calculator is needed to reverse the cosine square function, which is not part of this scenario. Hence, without precise calculations, it can be said a fairly large angle is required compared to 45° but less than 90°.