ta5bees

• • A wire carrying an electric current produces its own magnetic field, which is called induced magnetism or electromagnetism.
• A generator converts mechanical energy into electrical energy through electromagnetic induction.
• When a bar magnet moves towards a coil with wires connected across it, a potential difference (PD) is generated between the ends of the coil.
• If the bar magnet continues moving past the coil, the PD will continue until the magnet stops moving.
• The PD can be measured using a voltmeter.
• • A permanent magnet is made from iron or steel that has been magnetized using electricity.
• • The direction of the magnetic field depends on the direction of the electric current, with clockwise current creating an anticlockwise magnetic field around the wire.
• Electricity flows along a wire due to the movement of charged particles called electrons.
• • When the current flows into the page, the magnetic field lines point outwards from the wire.
• • Induced magnetism occurs when a material is exposed to a changing magnetic field.
• If the south pole of the magnet moves away from the coil, the induced magnetic field points downwards.
• If the north pole of the magnet moves towards the coil, the induced magnetic field points upwards.
• A generator converts mechanical energy into electrical energy by using a rotating loop of wire inside a permanent magnet.
• This causes a flow of charge (electrical current) around the circuit.
• The direction of the induced electric current depends on the direction of rotation of the loop of wire.
• An alternator produces an AC supply because the direction of the induced electric current keeps reversing.
• In a DC motor, the current flows through a split ring commutator which changes the direction of the current every half turn so that it always goes round in one direction.
• When the current is flowing out of the bottom of the coil, the force on the coil is to the left.
• When the current is flowing out of the top of the coil, the force on the coil is to the right.
• • AC current reverses direction repeatedly, while DC current flows in only one direction.
• • The frequency of AC is measured in hertz (Hz), with the standard frequency being 50 Hz or 60 Hz.
• A generator converts mechanical energy into electrical energy by using a rotating magnet near a stationary wire loop.
• Induction motors work similarly to generators but use a permanent magnet instead of a rotating magnet.
• Transformers are used to increase or decrease voltage levels without changing the power supplied.