| whats the motor effect | A wire carrying a current creates a magnetic field . This can interact with another magnetic field, causing a force that pushes the wire at right angles |
| what is magnetically hard? | Substances that can be permanently magnetised |
| magnetically soft | those materials that are easily magnetised and demagnetised. |
| why are some materials magnetised but not others? | most of the electrons spin in the same direction. This makes the atoms in these substances strongly magnetic |
| how are simple electromagnets made | wrapping a wire around an iron nail and running current through the wire. |
| loudspeaker | 1.a current in the coil creates a magnetic field
2.the magnetic field interacts with the permanent magnet generating a force, which pushes the cone outwards
3. the current is made to flow in the opposite direction
4.the direction of the magnetic field reverses
5. the force on the cone now pulls it back in
repeatedly alternating the current direction makes the cone vibrate in and out
6. the cone vibrations cause pressure variations in the air - which are sound waves |
| how to make an electromagnet stronger | more turns of coils, soft iron core, stronger magnet |
| what is electromagnetic induction | a voltage is induced in a conductor or a coil when it moves thru a mf or when a mf changes thru it |
| whats a split ring commutator | two metal half rings connecting either end of the rotor coils to the brushes |
| slip ring | passes electrical signals and power across a rotating interface using sliding electrical contacts. |
