PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
During midday sailing, a student notices intense glare from sunlight reflecting off the surface of calm water. Measurements show that the reflected light is nearly horizontally polarized. To reduce eye strain, the student purchases sunglasses equipped with polarizing lenses whose transmission axis is oriented vertically.
Answer all parts completely, providing clear explanations and any necessary calculations.
(a) Explain why light reflecting off a horizontal water surface becomes preferentially polarized in the horizontal direction.
(b) The incident sunlight may be taken as unpolarized with average intensity Isun. Assuming the polarizing lenses are ideal and absorb all components perpendicular to their transmission axis, determine the intensity of the reflected glare that reaches the student’s eyes when wearing the sunglasses.
(c) If the student tilts their head so that the transmission axis of the lenses makes an angle of 25∘ with the vertical, calculate the new intensity of the reflected glare reaching the eyes in terms of Isun.
(d) Discuss how the transverse nature of electromagnetic waves underlies both the polarization of the reflected light and the operation of the polarizing lenses.