Lecture20 - 1 February 22, 2008 Physics 132-Winter 2008...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 February 22, 2008 Physics 132-Winter 2008 Prof. Jim Beatty-Ohio State 1 Physics 132 Introductory Physics: Electricity and Magnetism Winter Quarter 2008 Lecture 20 February 22, 2008 Physics 132-Winter 2008 Prof. Jim Beatty-Ohio State 2 Combining Electric and Magnetic Fields x y z Electric Field gives F E =qE Magnetic Field gives F B =qv B Can we construct a combination of v, B and E to give uniform linear motion? Yes! v, E, and B all perpendicular. Try v along +x, B along -y, and E along +z. v is in E B direction. F E = q E = qE z F B = q v B = qvB ( x y ) = qvB ( z ) F tot = F E + F B = q ( E vB ) z F tot =0 if E=vB. This is a velocity selector! Only v=E/B goes straight. + B v E 2 February 22, 2008 Physics 132-Winter 2008 Prof. Jim Beatty-Ohio State 3 The Hall Effect x y z B = B z Electrons moving along a conductor feel a magnetic force that pushes them toward the side. This creates induced charge, and an electric field which cancels out the magnetic force for electrons at the drift velocity. (d=width, A=area) v d = E B = V Hall dB v d = J ne = i neA n = Bi eV Hall d A We get the number of (and sign) of charge carriers! i i- i i-- - - - - - - - - - + + + + + + + + + + v d February 22, 2008 Physics 132-Winter 2008 Prof. Jim Beatty-Ohio State 4 Force on a Current-Carrying Wire F = q v B dq v = dq d x dt = d x dq dt = i d x q v = i L F = i L B For moving point charges: How do we deal with moving charges forming currents on a wire?...
View Full Document

Page1 / 8

Lecture20 - 1 February 22, 2008 Physics 132-Winter 2008...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online