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Unformatted text preview: Physics 3123 (Spring 2011), 2nd Quiz 4/8/11
1. Calculate the reﬂection coeﬃcient for light at an air-to-copper interface
(µair ≈ µcopper ≈ µ0 , ǫair ≈ ǫ0 , σcopper = 6.0 × 107 Ω−1 m−1 ) at optical
frequencies (ω = 4 × 1015 /s). Use that σcopper ≫ εcopperω . The numerical
result is not required; you may give your answer in terms of the quantities
that are given above. (30 points) 2. Find the gradient of the scalar, retarded potential V (r, t) of a general
charge distribution ρ in terms of integrals involving ρ and its time derivative ρ. (30 points)
˙ 3. Consider a point charge that moves with a constant velocity v along the
positive x-axis of a cartesian coordinate system. At time t = 0 the charge
is located at the origin r = 0 of the coordinate system. Find the scalar
Li´nard-Wiechert potential V (0, t) and the electric ﬁeld E(0, t) produced
by the charge at the origin at times t > 0. (40 points) 1 ...
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This note was uploaded on 01/22/2012 for the course PHYS 3123 taught by Professor Kindermann during the Spring '11 term at Georgia Institute of Technology.
- Spring '11