Karteikarten
GCSE Physics - Electromagnets and Motors
Karten in diesem Stapel (17)
- 1When is a magnetic field produced around a wire?It occurs when an electric current flows in a wire.
- 2What are the three ways in which we can strengthen the magnetic field around a wire?wrapping coil around iron core
- adding more turns to coil
- increase current flowing in coil - 3What two things are needed to produce an electric current?A magnet and a coil of wire
- 4What is electromagnetic induction?When a magnet moves into a coil of wire, producing voltage.
- 5Give two ways the direction of voltage can be reversed.- the magnet is moved out of the coil
- other pole of magnet is moved into the coil - 6When only is voltage produced?When the magnet is moving inside the coil.
- 7What do field line patterns show?The direction and shape of a magnetic field.
- 8What are field line patterns usually drawn with?A plotting compass
- 9What do the arrows on field line diagrams represent?The direction from North to South poles.
- 10What is a solenoid?A long thin spiral of wire used to make magnetic fields.
- 11How do you increase the induced voltage?- move magnet faster
- add more turns to coil
- increase strength of magnet - 12Define the motor effect.When a current carrying wire or coil exerts a force upon a permanent magnet or another wire/coil.
- 13How can a simple electric motor be constructed?Using a coil of wire which can freely rotate between two opposing magnetic poles.
- 14Explain how a motor works.When electric current flows through the coil, it experiences a force and moves.
- 15What must be done to prevent the coil coming to a halt?The direction of current must be changed every half turn using a conducting ring split in two - also known as a split ring or commutator.
- 16What do speakers contain both of?A permanent magnet and an electromagnet.
- 17Explain how a speaker works.1) Electric current from amplifier is continually changing direction, which causes the magnetic field around the electromagnet to also continually change.
2) This causes the electromagnet to move back and forth.
3) Then, the speaker cone vibrates back and forth which generates sound waves. The frequency of these sound waves is determined by the frequency at which the current changes direction.
Informationen
- Beschreibung
- Add image of motor and Fleming's left/right hand rule
- Erstellt von
- Victoria Heath · Jan 2018
- Aktualisiert
- 10 Jan 2018
- Aufrufe
- 77
- Bewertung