How does a loop of wire in a generator produce alternating current?

[bruinboy28]

a.by creating current by rotating in an existing magnetic field?
b.by creating a varying magnetic field with its rotational kinetic energy
c.by rotating through areas of high and low electrical force


An electric field produces a magnetic field even when there is no wire to conduct a current provided which of the following is also true?

a.The electric field is between a pair of parallel metal plates.
b.The electric field changes in time but at each instant is the same at every location.
c.The electric field is changing as time passes.
d.The electric field is different from place to place.
e.The electric field does not change as time passes.

 

[hotcommodity]

It might help if you post some of your thoughts. For the first problem, consider the implications of Faraday's Law. For the second problem, consider Maxwell's extension to Ampere's Law (or Ampere's circuital law as it's named in this link): http://en.wikipedia.org/wiki/Maxwell's_equations

What's happening to the electric field E in this equation?

 

[Moetasim]

The correct answer is c. The electric field is changing as time passes. This is because a changing electric field creates a changing magnetic field, according to Maxwell's equations. This changing magnetic field then induces a current in the loop of wire in the generator, resulting in alternating current. Without a changing electric field, there would be no alternating current produced.