# A j r i b e0 c coskz t 2 r b b i

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Unformatted text preview: is in P HY S 2 1 4 Exercise Exercise An electromagnetic wave is described by: ˆ where is the unit vector in the +y direction. j y r E = ˆ 0 cos(kz − ωt ) jE x z Which of the following graphs represents the z-dependence of B x at t = 0? X X (A) (B) (C) (D) E and B are “in phase” (or 180o out of phase) r E = ˆ 0 cos(kz − ωt ) jE Wave moves in +z direction y rr E E × B points in direction of propagation x B BB r ˆ B = −iB0 cos(kz − ωt ) z Exercise Exercise An electromagnetic wave is described by: y r iˆ + ˆ j E= E0 cos(kz + ωt ) 2 x z What is the form of B for this wave? (A) ˆj r i+ˆ B= ( E0 / c) cos(kz + ωt ) 2 r ˆ ˆ (B) B = i − j ( E0 / c)cos(kz + ωt ) 2 r iˆ + ˆ j E = E0 cos(kz + ωt ) 2 y E x B r r E × B points in negative z-direction ˆj r −i + ˆ B= ( E0 / c) cos(kz + ωt ) (C ) 2 r −iˆ − ˆ j (D) B = ( E0 / c) cos( k...
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## This document was uploaded on 02/13/2014.

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