Electromagnetism Flashcards
(8 cards)
What pattern is the magnetic field around a current?
Circles. No north and south poles. The direction of the magnetic field depends on the direction of the current
In electromagnetism, whenever an electric current flows, it produces what?
A magnetic field. We can show this using a compass.
What happens if a wire is looped around a coil?
The fields of each loop add together to make a stronger field. A long coil of wire is called a solenoid. The field of a solenoid looks like the field of a bar magnet with a North Pole at one end and a South Pole at the other. Unlike a bar magnet is has very strong field going through the centre. Iron inside the solenoid would make a stronger electromagnet.
What are relay switches? How could they be used?
Magnetic switches are called relays,they let a small current switch on a large current. In a car the key switches on the ignition, thin wires connect the ignition to the battery because a small current of one amp is needed. The starter motor needs 100 amps to start, so thick wires connect to the battery. A relay switch lets the ignition circuit control the motor circuit
How does a lifting magnet work? And how could it be used in a device?
In a burglar alarm an alarm could ring if a window is opened, the window has a magnet built into it and a switch fixed to the window frame. When window is closed the magnet attracts the switch, the switch is pulled away from the circuit. When window open the switch turns on.
What is an electro magnet?
A magnet, that has been magnetised by electricity. Coils of wire are wrapped around an iron (which works best) core electricity runs through the wire. Magnetising the core.
Does an electro magnet have a north and South Pole.
Yes but it depends on where the coils come from. Whichever side the coils start on, is the north as the coils act like the magnetic field, which goes North to South.
Does an electro magnet have a magnetic field?
Yes, the solenoid acts as the magnetic field similar to that of a bar magnet.
