Physics 2102 QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Jonathan Dowling Lecture 32 WED 01 APR Review Session Midterm 3 QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture EXAM 03 6PM THU 02 APR LOCKETT 5 EXAM 03 REVIEW 6PM WED 01 APR NICHOLSON 130 The exam will cover Ch 28 second half through Ch 32 13 displacement current and Maxwell s equations The exam will based on HW08 formula sheetbe for the exam can be found here HW11 www phys lsu edu classes spring2009 phys2102 formulasheet an see examples of old exam IIIs here www phys lsu edu classes spring2009 phys2102 Test3 oldtest QuickTime and a decompressor are needed to see this picture r F iLBsin r Bsin B cos r QuickTime and a decompressor are needed to see this picture r B Highest Torque 90 sin 1 Lowest Torque 0 90 sin 0 QuickTime and a decompressor are needed to see this picture 180 cos 1 0 cos 1 QuickTime and a decompressor are needed to see this picture ght Hand Rule Given Current i Find Magnetic Field QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Checkpoints Questions Magnetic field Force on each wire due to currents in the other wires Ampere s Law Find Magnitude of B ds ght Hand Rule Given Current i Find Magnetic Field The current in wires A B D is out of the page current in C is into the page Each wire produces a circular field line going through P and the direction of the magnetic field for each is given by the right hand rule So the circles centers in A B D are counterclockwise the circle centered at C is clockwise When you draw the arrows at the point P the fields from B and C are pointing in the same direction up and left Right Hand Rule Biot Savart Given i Find B A length of wire is formed into a closed circuit with radii a and b as shown in the Figure and carries a current i a What are the magnitude and direction of B at point P B b Find the magnetic dipole moment of the circuit 0i 4 R r B NiA QuickTime and a decompressor are needed to see this picture Lenz s Law QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Induction and r r Inductance d d E ds Faraday s law E or dt B C B dt Inductance L N I For a solenoid L 0n2Al 0N2A l Inductor EMF EL L di dt RL circuits i t E R 1 e tR L or i t i0e tR L RL Time Constant L R Units s Magnetic energy U Li2 2 Units J Magnetic energy density u B2 2 0 Units J m3 i Changing B Flux Induces EMF QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Flux Up RL Circuits Flux Down E iup t 1 e tR L R 1 2 U B t Li 2 1 E2 tR L 2 L 2 1 e 2 R E tR L idn t e R 1 2 U B t Li 2 1 E 2 2tR L L 2e 2 R E tR L iup t e L VL Li E tR L e L E tR L iup t e L VL Li E tR L e L RL Circuits E 2 QuickTime and a decompressor are needed to see this picture t QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Checkpoints Questions Magnitude direction of induced current Magnitude direction of magnetic field inducing current Magnitude of induced emf current Given E ds direction of magnetic field Given B dB dt magnitude of electric field Current inducing EL Largest L Current through the battery Time for current to rise 50 of max value Largest current R L or 2R L or R 2L or 2R 2L When the switch is closed the inductor begins to get charged and the current is i E R 1 e tR L When the switch is opened the inductors begins to discharge The current in this case is then i E R e tR L QuickTime and a decompressor are needed to see this picture E LC Circuits q t E C cos t i t q t E C sin t i t q t 2E C cos t 1 2 1 2 U B t Li t L E C sin t 2 2 Units L 2E 2C 2 s2 C V s2 V C J VL t Li t L 2E C cos t Units L 2E C s2 s2 V V LC Circuits QuickTime and a decompressor are needed to see this picture q t E C cos t QuickTime and a decompressor are needed to see this picture qmax EC q T i imax EC i t q t E C sin t QuickTime and a decompressor are needed to see this picture Frequency f 2 Hertz Angular Frequency f rad s QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture IP IS QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture r QuickTime and a decompressor are needed to see this picture
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