Electromagnetic Induction, Power Generation and Transformers

Question 1

What is electromagnetic induction?

Answer 1

It’s the production of an electromagnetic forces across an electrical conductor in a changing magnetic field

Question 2

What is Faraday’s Law?

Answer 2

The EMF produced is proportional to the change in flux over time

Question 3

What is Lenz’s Law?

Answer 3

The direction of the induced current will be such that the magnetic field produced by the induced current will oppose the change in flux that induced the current

Question 4

What are eddy currents?

Answer 4

The loops of electrical current induced within conductors by a changing magnetic field. These currents flow in closed loops perpendicular to the magnetic fields

Question 5

What is a transformer?

Answer 5

A device that increases and decreases AC voltage

Question 6

How does a transformer work?

Answer 6

1. It has a primary and secondary coil
2. The change of flux originates in the alternating current of the primary coil
3. The change in flux is directed to the secondary coil where it induces an EMF
4. The voltage in the 2nd coil depends on the number of turns in each coil

Question 7

What is the difference between a step-up transformer and a step-down transformer?

Answer 7

Step-up: The number of the coils in the second is greater than the number of coils in the first. This creates a greater voltage in the second coil.
Step-down: The number of the coils in the second is lessened than the number of coils in the first. This creates a lower voltage in the second coil.

Question 8

What is a generator?

Answer 8

It is a coil that is rotated in a magnetic field. An induced EMF is produced as the magnetic flux within the coil is continually changing.

Question 9

What is back EMF?

Answer 9

Is an electromotive force or voltage that opposes the change in current that induced it.