This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Exam III Solutions Part A. Multiple choice questions. Check the best answer. Each question carries a value of 4 points. 1. A radio is being tuned to a local station. At Frst there is no discernible signal from the antenna. Then the capacitance of the tuning circuit (a series LCR circuit with the antenna as emf) is increased slightly and the local station’s signal is received clearly. Which of the following is wrong? √ The station’s frequency is higher than the one originally tuned to. [Lower.] The same result would have occurred if the inductance had been increased instead of the capacitance. Before the capacitance was changed, the rms voltage across the capacitor was greater than across the inductor. One of the above is wrong. 2. At a given place and time the E-Feld of a light wave is in the + y-direction and its B-Feld is in the + x-direction. The wave is propagating in the + z-direction. [- z .] If a polaroid Flter with transmission axis in the y-direction is placed in the path of the wave, the wave’s energy will be absorbed by the Flter. [Transmitted.] √ A possible formula for the E-Feld is E = E cos( kz + ω t ) j . The E and B Felds have the same amplitude. [ E = cB .] Physics 54 Summer 2010 1 3. Unpolarized light is incident at angle θ 1 from a medium with refractive index n 1 onto the interface with a medium of refractive index n 2 . The light is totally reFected. Which of the following is wrong? If θ 1 < 90 ° then n 2 < n 1 . If n 2 > n 1 then θ 1 = 90 ° . √ The reFected light is partially polarized with E perpendicular to the plane of incidence. [Remains unpolarized.] If n 2 < n 1 then θ 1 is greater than the critical angle. [Or equal.] 4. Concerning defects of vision, which of the following is wrong?...
View Full Document
This note was uploaded on 10/19/2011 for the course PHYSICS 54L taught by Professor Thomas during the Summer '09 term at Duke.
- Summer '09