P12 | magnetism & motor effect

Question 1

what is a magnetic field?

Answer 1

a region of space around a magnet where magnetic materials and current carrying wires experience a non-contact force

Question 2

when do induced magnets have a magnetic field?

Answer 2

when they inside another magnetic field

Question 3

what is induced magnetism?

Answer 3

when a permanent magnet causes a non-magnetic object (e.g. paperclip) to become magnetic, which causes another paper clip to become magnetic and so on

Question 4

four magnetic elements:

Answer 4

• iron
• nickel
• cobalt
• steel

Question 5

drawing magnetic field lines:

Answer 5

1) always go from north to south
2) magnetic field lines are closer at the poles
3) magnetic field lines get further apart the further away from the magnet they are
4) magnetic field lines never overlap

Question 6

how to find the direction of magnetic field using compasses:

Answer 6

• place the compass at one pole of the magnet and make a dot next to it showing the direction the compass arrow points
• move the compass so that the base of the arrow is at the dot you’ve just made. now make a new mark where the tip of the arrow is pointing this time
• keep doing this until you reach the other end of the magnet. connect the dots

(to improve this method, you could use more compasses, plot more points OR use iron filings to show magnetic field lines)

Question 7

how/why do we know that the Earth has a magnetic field?

Answer 7

because all compasses point to the north pole

Earth’s core contains nickel and iron which are magnetic