P7 Magnetism

Question 1

Magnetic Field

Answer 1

A region where other magnets or magnetic materials experience a force

Question 2

Magnetic materials

Answer 2

Nickel
Iron
Cobalt
Steel

Question 3

Draw lines repulsion and attraction

Answer 3

N -> ->S
N-><-N

Question 4

Types of magnet
Explain each

Answer 4

Permanent magnets produce their own magnetic field always
Induced magnets are magnetic materials that become magnetic in a magnetic field
The force between them is always attractive

Question 5

Electromagnetism

Answer 5

When current flows through a wire a magnetic field is created aorund the wire

Question 6

How to increase magnetism of a solenoid

Answer 6

Increase the current
Increase numebr of coils
Decrease the length
Place an iron core in the centre to create an induced magnet

Question 7

3 uses of electromagnets

Answer 7

Cranes
Loudspeakers
Motors

Question 8

Motor effect

Answer 8

When a current carrying wire is put between magnetic poles the magnetic field around the wire interacts with the magnetic field it has been placed in. This causes the wire and magnet to exert a force on each other

Question 9

Rules of the motor effect

Answer 9

The force always acts at right angles.
To experience the full force it has to be 90 degrees to the magnetic field
The strength of the force increases with strength of magnetic field and amouint of current

Question 10

Motor force equation with units

Answer 10

F= BIL

Force=Magnetic flux density Current Length

Newtons=Tesla Amps metres

Question 11

Flemings left hand rule

Answer 11

Using your left hand
First finger in direction of field
Second motion
Thumb motion/force

Question 12

What is a split ring commutator and why is it needed

Answer 12

Swaps the positive and negative connections every half turn. So that the coil can trun 360 degrees and so that direction of current swaps every half turn