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Unformatted text preview: A uniform electric field is confined to a circular region of radius, r , and is increasing with time. What is the direction and magnitude of the induced magnetic field at the radius r? Answer: If I choose my orientation to be counterclockwise then E = E(t)A with A = r 2 . Amperes Law ( with J = 0 ) tells us that r r B dl rB r d dt r c dE dt E Circle = = = 2 2 2 ( ) , and hence B(r) = (r/2c 2 ) dE/dt . Since dE/dt > 0 ( increasing with time ), B is positive which means that it points in the direction of my chosen orientation. B-out increasing with time r E E-out increasing with time r B...
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This note was uploaded on 05/31/2011 for the course PHY 2061 taught by Professor Fry during the Spring '08 term at University of Florida.
- Spring '08