Electromagnetic Induction

The Physics Hypertextbook™
© 1998-2008 by Glenn Elert -- A Work in Progress
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Discussion

introduction

Motional emf

V = Blv

Faraday's Law is in another section

ℰ = −  dΦB
dt

During top level geomagnetic storms (G5 out of 5) pipeline currents can reach hundreds of amps. On average these occur 4 times every 11 year solar cycle and last about 4 days each.

electric generator

A generator is a backward motor.

dynamic microphone

A dynamic microphone is a backward speaker.

Microphones and How They Work
type sounds produce
changes in … 		which cause
changes in … 		which result in
changes in …
carbon granule density resistance voltage
condenser plate separation capacitance voltage
dynamic coil location flux voltage
piezoelectric compression polarization voltage

Summary

Problems

practice

  1. Write something.
    • Answer it.
  2. Write something.
    • Answer it.
  3. Write something.
    • Answer it.
  4. Write something completely different.
    • Answer it.

conceptual

  1. The diagram to the right shows a segment of a wire as it moves through a region of uniform magnetic field B. Show the direction of the induced current flow through the wire.
   
  1. In what direction should the wire be moved through the magnetic field so as to induce the current indicated in the diagram to the right?
   
  1. The diagram to the right shows the instantaneous position of a rotating loop of wire between two bar magnets. The loop is rotating clockwise when viewed from P. The magnets and the loop all lie in the same plane. Indicate the direction of induced current flow in the loop.

Resources

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