3.7.5.4 - Electromagnetic Induction

Question 1

What is Faraday’s law?

Answer 1

Induced emf is directly proportional to the rate of change of flux linkage.

Question 2

Magnitude of induced emf =

Answer 2

Rate of change of flux linkage

Question 3

What is the gradient of a flux linkage time graph?

Answer 3

Emf

Question 4

What is the area under an emf time graph?

Answer 4

N Δ flux linkage

Question 5

What is Lenz’s Law?

Answer 5

The induced emf is always in such a direction as to oppose the change that caused it.

Question 6

What happens when a coil rotates uniformly in a magnetic field?

Answer 6

The coil cuts the flux and an alternating emf is induced.

Question 7

What is emf proportional to?

Answer 7

Angular speed - the greater the speed of spin, the greater the induced emf.

Question 8

When is emf zero?

Answer 8

When the coil is perpendicular to the magnetic field.

Question 9

What happens to the emf and frequency when B, the magnetic flux density, is increased?

Answer 9

Will increase the max emf, but will have no effect on the frequency.

Question 10

When is flux linkage max?

Answer 10

At 0 and 180 degrees - when the coil is perpendicular to the magnetic field.