P4.1 - Magnetism

Question 1

what is used to model a magnetic field?

Answer 1

magnetic field lines

Question 2

what is the number of field lines passing through a particular area called?

Answer 2

magnetic flux density/ magnetic field strength

Answer 3

.

Question 4

what does the density of field lines show?

Answer 4

the strength of the magnetic field

Question 5

give an example of an induced magnet

Answer 5

when a paperclip is attracted to a magnet

Question 6

why does steel not always have magnetic properties?

Answer 6

as its domains are not always lined up

Question 7

why does steel and iron become magnetic when in a magnetic field?

Answer 7

as it causes the domains to line up in the same direction (towards a pole)

Question 8

why do permanent magnets stay lined up when a magnetic field is removed, but (soft) magnetic materials do not?

Answer 8

as the domains continue to be lined up (permanent), but in a (soft) magnet, they revert back to their original direction

Question 9

where does a compass point?

Answer 9

magnetic north pole (which is geographical south pole)

Question 10

which way do field arrows point around a bar magnet?

Answer 10

north to south

Question 11

how can you work out the direction of a magnetic field around a current?

Answer 11

using the RIGHT hand rule

Question 12

if the current is coming towards you, which way would the field lines be going?

Answer 12

anti-clockwise

Question 13

What does the strength of the field around the wire depend on

Answer 13

• magnitude of the current

- distance from the wire (closer to wire, stronger field)

Question 14

What is the strength of a magnetic field measured in (units)?

Answer 14

Teslas (T)

Question 15

what is the strength of the earth’s magnetic field?

Answer 15

0.01 mT

Question 16

What is a solenoid?

Answer 16

a coil of wire that carries a current

Question 17

how do you make fields of a solenoid stronger?

Answer 17

putting a magnetic material inside the core

Question 18

what does putting a magnetic material inside am solenoid produce?

Answer 18

an induced magnet

Question 19

what is magnetism?

Answer 19

the ability of magnets to attract and repel other magnetic without contact

Question 20

what are the only pure metals that can be turned into magnets (magnetic materials)?

Answer 20

iron, nickel, cobalt

Answer 21

-

Question 22

what can magnets attract and repel?

Answer 22

• they can attract and repel other magnets

Question 23

which kind of magnets produce a magnetic field?

Answer 23

only permanent magnets

Question 24

what is the difference between permanent and induced magnets?

Answer 24

• permanent magnets are always magnetic, and always have poles
• induced magnets are only magnetic when have a permanent magnet near them - do not always have poles

Question 25

how does the behaviour of a magnetic compass relate to evidence that the core of earth must be magnetic?

Answer 25

• magnet points towards magnetic north pole

Question 26

what four factors affects the strength of the field produced on a solenoid?

Answer 26

• size of current
• distance from conductor
• number of coils
• type of core used