This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Lecture 16 Magnetic Fields generated by Currents Good luck tonight! Sources of B field • B fields exert forces on moving charges and currents (ch. 27) • Oersted experiment makes it clear that currentcarrying wires exert forces on compass needles Moving charges and currents generate B fields (ch.28) B generated by a moving charged particle—read 28.1 B generated by currents—our primary focus for today Demos: Oersted/tangent galvanometer BiotSavart law (circa 1820) ( of a current element) 2 2 ˆ 4 sin 4 r r l Id B d r Idl dB in in × = = π μ ϕ π μ B = B = I dl r (dB out) (dB in) μ = 4π x 107 Tm/A Integrate along wire path to get total contribution to B at point P P B d φ Field lines around current element (end/axial view) B for a finite straight wire segment ) sin (sin 4 cos 4 cos cos cos 4 2 1 2 2 2 1 2 1 2 θ θ π μ θ θ π μ θ θ θ θ π μ θ θ θ θ + = = = ∫ ∫ x I B d x I B x xd I B x Idl P θ 1 θ 2 For an ∞ wire, θ 1 and θ 2 go to 90°...
View
Full
Document
This note was uploaded on 04/04/2008 for the course PHYSICS 240 taught by Professor Davewinn during the Spring '08 term at University of Michigan.
 Spring '08
 DaveWinn
 Charge, Current, Force

Click to edit the document details