magnetism - the generator effect

Question 1

what happens when we move a wire through a magnetic field? but what happens when wire stops moving? what happens when we move it back down again?

Answer 1

a potential difference is induced across the ends of the wire however when it stops then the potential difference is lost. when moved back down we get potential difference but it has now reversed direction (called the induced potential difference)

Question 2

what happens when we use a complete circuit?

Answer 2

we are inducing a current (generator effect)

Question 3

the direction of the current switches when…

Answer 3

the direction of movement switches. if movement stops so does current

Question 4

when do we get an induced potential and induced current?

Answer 4

if we keep the wire still but move the magnetic field

Question 5

when do we see the generator effect?

Answer 5

if the wire passes through the magnetic field (not other way around). if wire moves along magnetic field we don’t get an induced potential difference or current

Question 6

what does the size of potential difference or current depend on?

Answer 6

larger if we use:
- stronger magnetic field
- move wire more rapidly
- shape wire into coil (greater number of turns on the coil then the greater the induced potential difference and current)

Question 7

what happens when a magnet moves in and out of a coil of wire?

Answer 7

• produces an induced current in wire. this induced current produces its own magnetic field. this opposes movement of magnet so when we insert north pole into coil, that end of coil becomes a north pole. this repels magnet, making it harder to push magnet in (we are doing work, we are transferring energy from movement of magnet into movement of current) . when we pull it out, that end of coil becomes south pole. attracts magnet making it harder to pull it out
• direction of current changes when direction of movement changes
• switch direction of induced current also by switching the poles of the magnet

Question 9

what is the generator effect?

Answer 9

if conducting wire moves into magnetic field then a potential difference is induced in wire but if circuit moved then induced current produces its