Magnetism

Question 1

What is magnetism?

Answer 1

The force of a magnet that attracts or repels an object

Question 2

How can we see and measure magnetic field?

Answer 2

By scattering tiny filings around the material.
The closer they are, the stronger is the magnetic field.

Question 3

What way do the field lines flow

Answer 3

From north to south pole

Question 4

Where is the cause of magnetism from

Answer 4

ATOMS

if a magnet is cut into its smallest form it still possesses the properties. So must be atoms

Question 5

What does magnetism of a material depend on

Answer 5

Presence of atomic dipoles which arise from electrons spinning and orbitting around the nucleus

Question 6

Are dipoles arranged

Answer 6

No, random and dont give net magnetism

Question 7

If an atom is magnetic does it mean the materials made up OF it are

Answer 7

NO

Question 8

Define Ferro Magnetic

Answer 8

All atoms line their magnetic field - magnetic

Question 9

Define anti-ferromagnetic

Answer 9

Magnetic fields are in alternating fashion and all cancel out

Question 10

Define paramagnetic

Answer 10

Random - not magnetic

Question 11

What is a domain

Answer 11

Areas in magnetic material that may not be magnetic

Question 12

How to make domains magnetic

Answer 12

If you apply a strong enough magnetic field outside the material it will align all domains and all will become magnetic

Question 13

What happens when a wire carries a current

Answer 13

A magnetic field is created around it

Question 14

How do we demonstrate a wire carrying current

Answer 14

Placing a compass next to it,
deflection noticed.

Question 15

What is done to a conductor in order to make it more magnetic

Answer 15

Wound into a solenoid

Question 16

Why does a conductor become more magnetic when wound into a solenoid

Answer 16

As with each turn of the wire, it becomes more magnetic and it is reinforced by the next form

Question 17

How can you increase the strength of a solenoid

Answer 17

We can insert a piece of ferromagnetic material called a core, which becomes materialised

Question 18

What is an electromagnet

Answer 18

A solenoid with a soft iron core

Question 19

What does a soft iron core do?

Answer 19

Does not retain its magnetism when switched off, so we have a magnet which can be turned on and off.

Question 20

Where are electromagnets used?

Answer 20

• Removing foreign bodies patients eyes
• Brakes on XRAY machine
• CT to alter focal spots

Question 21

How are electromagnetics used in MRI

Answer 21

Spinning charge of hydrogen in the body causes a magnetic field, the movement in the magnetism across the receiver induces a current in coil which is measured.

Question 22

What is Faradays Law

Answer 22

magnitude of the induced electromotive force is directly proportional to the rate of change of magnetic flux linked with the circuit.

Question 23

What does size of current induced in conductor depend on

Answer 23

• strength of magnetic field
• speed of magnet movement
• angle of conductor
• number of coil turns