Electromagnetism

Question 1

Describe how electromagnetism works

Answer 1

An electric current in a conductor produces a magnetic field
The larger the current, the stronger the magnetic field
The direction of the magnetic field is proportional to the direction of the current

Question 2

Describe the magnetic field around a straight wire

Answer 2

Concentric circles with the wire in the centre

Question 3

Describe the magnetic field around a flat circular coil

Answer 3

Concentric ellipses of magnetic field lines around the coil

Question 4

Explain how you can make an electromagnet

Answer 4

Current carrying wire coiled as a solenoid with a soft iron core

Question 5

What does it mean if a magnetic material is ‘soft’

Answer 5

It loses its induced magnetism easily e.g. iron

Question 6

What does it mean if a magnetic material is ‘hard’

Answer 6

It keeps its induced magnetism permanently e.g. steel

Question 7

How can you increase the strength of the magnetic field around a solenoid

Answer 7

By adding a ‘soft’ iron core

Question 8

What is electromagnetic induction

Answer 8

The creation of voltage in a wire which is experiencing a change in magnetic field