Magnetism And Electromagnetism

Question 1

What is a magnetic field ?

Answer 1

A region where other magnets or magnetic materials experience a non - contact force

Question 2

What ways do the arrows go to show a magnetic field ?

Answer 2

North to south

Question 3

What happens when the lines are closer together and what happens when the lines are further away ?

Answer 3

Closer together - the stronger the magnetic field

Further way - the weaker the magnetic fields

Question 4

How can you find the magnetic field of a bar magnet ?

Answer 4

Move a compass around the magnet and trace the position the arrows points around the magnet

Question 5

What way do compasses point when not near a magnet and why ?

Answer 5

North - earth generates its own magnetic field

Question 6

What are the two types of magnets ?

Answer 6

Permanent and induced

Question 7

What is an induced magnet ?

Answer 7

Magnetic materials that turn into a magnet when they are put into a magnetic field

Question 8

What are permanent magnets ?

Answer 8

Magnets that produced their own magnetic field

Question 9

What happens to induced magnets when you take away their magnetic field ?

Answer 9

Quickly loose their magnetism and stop producing a magnetic field

Question 10

What is the magnetic field like when a current flows through a wire ?

Answer 10

Made up of concentric circles perpendicular to the wire , with the wire in the centre
You can see this by placing a compass near a wire carrying the current and as you move the compass around it will trace the direction of the magnetic field

Question 11

The larger the current through through the wire or the closer to the wire you are the …..

Answer 11

Stronger the field is

Question 12

What is the motor effect ?

Answer 12

When the magnetic field around a wire interacts with the magnetic field it has been placed in , this causes the magnet and conductor to exert a force on each other and can cause the wire to move

Question 13

How does the motor effect work ?

Answer 13

The wire must be at 90° to the magnetic field . If the wire runs parallel to the magnetic field it won’t experience any force. At angles in between will feel some force

The force always acts at right angles to the magnetic fields of the magnet and directions of the current In the wire

Question 14

What 3 things does the force acting on a conductor depend on ?

Answer 14

Magnetic flux density
Size of current
Length of conductor in the magnetic field

Question 15

What is the equation that involves force , current , magnetic flux density and length ?

Answer 15

Force = magnetic flux density X current X length

Question 16

What is Flemings left hand rule and what does it show ?

Answer 16

It can be used to find the direct of the force

It shows that if either the current Or the magnetic field is reversed then the direction of the force will also be reversed

Question 17

How does Flemings left hand rule work ?

Answer 17

Using your left hand :

1) point your First finger in the direction of the magnetic Field
2) point your seCond finger in the direction of e Current
3) your thuMb will then point in the direction of the force ( Motion )