Electromagnets, FLHR, Motor Effect and Transformers

Question 1

How can you increase the strength of an electromagnet?

Answer 1

1) Adding an iron core
2) Adding more turns to the coil
3) Increasing the current flowing through the coil.

Question 2

How can field lines be reversed?

Answer 2

Switching the direction of current.

Question 3

What does Fleming’s Left Hand Rule show and what does each finger show?

Answer 3

ThuMb=Motion
First finger=Field
SeCond finger=Current

Question 4

Which way does current flow?

Answer 4

Positive to negative.

Question 5

Which way do magnetic field lines flow?

Answer 5

North to South

Question 6

How do you work out which way a coil is turning in a simple motor?

Answer 6

1) Pick a side of the coil to apply rules to
2) Draw on the direction of magnetic field line (N—> S)
3) Draw on the direction of current( + to -)
4) Use Fleming’s left hand Rule.

Question 7

What is the Motor Effect?

Answer 7

The force experienced by current-carrying wire in a magnetic field.

Question 8

What is Electromagnetic Induction?

Answer 8

The creation of a POTENTIAL DIFFERENCE across a CONDUCTOR when in a CHANGING magnetic field.

Question 9

What does the primary coil do to induce electro

Answer 9

A constantly changing magnetic field, because of AC current)

This is ‘felt’ by the secondary coil, INDUCING an alternating voltage in the secondary coil.