P7- magnetism and electromagnetism

Question 1

what is a permanent magnet?

Answer 1

a permanent magnet produces its own magnetic field and will not loose its magnetism unless physically altered or damaged. (horseshoe and neodymium)

Question 2

what is an induced magnet?

Answer 2

a magnetic material that becomes a magnet if placed in a magnetic field. (paper clips and iron filings)

Question 3

what is a temporary magnet?

Answer 3

an object that will only become a magnet under certain conditions (electromagnets)

Question 4

what is a magnetic field

Answer 4

a region surrounding an object where a force acts on another magnet or magnetic field

Question 5

in what direction do the magnetic field move in?

Answer 5

from north to south

Question 6

where is the magnetic field strongest?

Answer 6

at the poles.

Question 7

how does a compass work?

Answer 7

it contains a tiny bar magnet. the North Pole of the magnet is attracted to the South Pole of any other magnet so will turn and point in that direction.

Question 8

what happen if a compass isn’t near any magnets?

Answer 8

it will always face north. this is because the earth generates its own magnetic field which shows the core if the earth must be magnetic.

Question 9

what are the two types of magnets?

Answer 9

permanent and induced

Question 10

what does a moving charge create and where does it typically happen?

Answer 10

creates a magnetic field

when a current flows through a wire, a magnetic field is created around that wire

Question 11

what does changing the direction and strength of a current do to a magnetic field

Answer 11

changing direction- changes direction of magnetic field

changing strength- changes strength of magnetic field. (stronger current, stronger mf)

Question 12

what is a solenoid?

Answer 12

a coil of wire with a current running through

Question 13

what does wrapping the wire into a solenoid do?

Answer 13

makes the magnetic field stronger

Question 14

how can you increase the strength of a solenoid?

Answer 14

wrap it around an iron core which becomes induced whenever a current is flowing.

Question 15

what does a current in a magnetic field experience?

Answer 15

a force

Question 16

to experience a full force, how should the wire be positioned?

Answer 16

90° to the magnetic field.

Question 17

how does the force increase?

Answer 17

• if the amount of current passing through the conductor increases.
• if the strength of the magnetic field increases.

Question 18

how can you find the size of a force?

Answer 18

use F=BIL

force=magnetic flux density(Tesla) x current (I) x length (m)

Question 19

explain how to find the direction of the force.

Answer 19

using Flemmings left hand rule
position hand like so:
-thuMb = Motion (force)
-First Finger= Field
-seCond finger= Current

Question 20

in a motor what happens if you reverse the batteries.?

Answer 20

the motor turns the other way

Question 21

what happens to a Motor when a magnet is removed or both magnets?

Answer 21

motor doesn’t turn or move. (stops working)

Question 22

what happens when a battery is added in series?

Answer 22

the motor spins quicker (increased current)

Question 23

what can you use to determine the direction the coil will turn?

Answer 23

lemmings left hand rule
thuMb-motion (force)
First Finger-field
seCond finger-current