Magnetism

Question 1

What direct do magnetic field lines go

Answer 1

• Forms loops going from the north to the south
• arrows going outwards from each pole
• the closer together they are, the stronger the magnetic field

Question 2

What is a magnetic field

Answer 2

• a region in which a magnetic material experiences a force

Question 3

What are the 3 magnetic materials

Answer 3

Nickel, iron and cobalt

Question 4

Which repel and attract

Answer 4

Like poles repel
Opposite pole attract

Question 5

Using a compass to determine field direction

Answer 5

• place a plotting compass at different points around bar magnet
• compass needle follows the direction of the field lines

Question 6

Compasses and the Earth’s magnetic field

Answer 6

• all compasses on Earth point to the geographic North Pole
• as all compasses line up with the magnetic field and are south seeking
• magnetic South Pole is the geographical North Pole

Question 7

What is an induced magnet

Answer 7

• when you bring a magnetic into the magnetic field of a bar magnet, the material will temporarily create its own magnetic field
• it will get attracted to magnet, the part of the material facing the magnet becomes the opposite pole so it can attract
• if the material is moved away it will eventually lose its magnetism
• these are called induced magnets

Question 8

What are permanent magnets

Answer 8

• produce their own magnetic field
• they don’t lose their magnetism

Question 9

What happens when a current flows through a wire

Answer 9

• when a current flows through a wire, a magnetic field is created around the wire
• the field is made up of concentric circles with the wire in the middle
• changing the direction of the current changes the direction of the magnetic field
• the greater the current through the wire, or the closer to the wire you are, te stronger the magnetic field

Question 10

What is the right hand thumb rule

Answer 10

• using your right hand, point your thumb in the direction of the wire and curl your fingers
• the direction of your fingers is the direction of the field

Question 11

What are solenoids

Answer 11

• you can increase the strength the magnetic field of a wire by wrapping it into a coil called a solenoid
• the field lines of each loop in the wire line up with each other closely and point the same direction , creating a stronger field
• outside the solenoid, the magnetic field lines are the same as any magnet

Question 12

What are electromagnets

Answer 12

• a solenoid but with a magnetic (usually iron) core in the middle
• the core becomes and induced magnet when current is flowing through the wire
• if you switch the current off, the magnetic field disappears
• electromagnets can be turned on and off

Question 13

What is the motor effect

Answer 13

A current carrying wire in the presence of a magnetic field will experience a force
- when we place a current carrying wire with a magnetic fuel in between 2 opposite poles with their own magnetic field, the 2 magnetic fields will interact
- this results in a force on the wire, pushing it out of the field
- to experience the full force, the wire must be exactly 90 degrees to the magnetic field of the magnets
- if the wire was parallel to the magnetic field it would experience no force