Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 22.45
Light polarized at a 45° angle (as seen traveling towards you) passes through a set of two ideal polarizing sheets. If the amount of light transmitted after passing through both polarizers is 25% of the original polarized light, the first polarizer transmission axis is ________, and the second polarizer transmission axis is __________.
(A) horizontal; parallel to the original light polarization.
(B) parallel to the original light polarization; horizontal.
(C) (Both of the above choices.)
(D) (None of the above choices.)
Correct answer (highlight to unhide): (A)
From Malus' law, the fraction of polarized light passing through a polarizer is given by cos2θ, where θ is the angle between the original polarization and the transmission axis of the polarizer. If θ = 0°, then the polarized light is parallel to the transmission axis of the polarizer, then all of the light will pass through the polarizer.
Thus only the first set of polarizers will pass "25% of the original polarized light."
Sections 30882, 30883
Exam code: quiz01c0Co
(A) : 19 students
(B) : 6 students
(C) : 18 students
(D) : 5 students
Success level: 40%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.51