Summary of observations
| Direction of movement of magnet | Needle of ammeter | Current flows? Yes or No |
| Magnet is stationary outside of coil | Remains at zero | No |
| South pole moves into coil | Deflects in one direction and then returns to zero | Yes, while the magnet is moving |
| Magnet is stationary inside of coil | Remains at zero | No |
| South pole moves out of coil | Deflects in the opposite direction and then returns to zero | Yes, while the magnet is moving |
| Direction of movement of magnet | Magnet is stationary outside of coil |
|---|---|
| Needle of ammeter | Remains at zero |
| Current flows? Yes or No | No |
| Direction of movement of magnet | South pole moves into coil |
|---|---|
| Needle of ammeter | Deflects in one direction and then returns to zero |
| Current flows? Yes or No | Yes, while the magnet is moving |
| Direction of movement of magnet | Magnet is stationary inside of coil |
|---|---|
| Needle of ammeter | Remains at zero |
| Current flows? Yes or No | No |
| Direction of movement of magnet | South pole moves out of coil |
|---|---|
| Needle of ammeter | Deflects in the opposite direction and then returns to zero |
| Current flows? Yes or No | Yes, while the magnet is moving |
Key points
The size of the current can be increased by:
- moving the magnet faster into and out of the coil;
- adding more turns to the coil;
- increasing the strength of the magnet.
The current that flows when a magnet moves into and out of a coil is an alternating currentAlso called ac. An electric current that regularly changes its direction and size..
The process is the basis of electricity generation in power stations and wind generators.
The energy change is:
kinetic energyEnergy which an object possesses by being in motion. \(\rightarrow\) electrical energy.