PHYS 102 Chapter Notes - Chapter 21: Electric Generator, Electric Field, Inductance

• School: McGill University
• Department: Physics
• Course: PHYS 102
• Professor: Nick Provatas

Document Summary

The magnetic flux passing through a loop is equal to the product of the area of the loop times the perpendicular component of the magnetic field strength: If the magnetic flux through a coil of wire changes in time, an emf is induced in the coil. The magnitude of the induced emf is induced in the coil. The magnitude of the induced emf equals the time rate of change of the magnetic flux through the loop times the number (cid:1840) of loops in the coil: The induced emf can produce a current whose magnetic field opposes the original change in flux (lenz"s law). An electric generator changes mechanical energy into electrical energy. A motor, which operates in the reverse of a generator, acts like a generator in that a back emf, or counter emf, is induced in its rotating coil. Because this back emf opposes the input voltage, it can act to limit the current in a motor coil.