Electromagnet Questions & Answers

Electromagnet Questions & Answers Advantages of electromagnets over permanent magnet? - ANSWER: They can be turned on and off; the strength of the magnetic field can be varied Best use of an electromagnet? - ANSWER: toasters and doorbells Commutator or slip ring - ANSWER: Fixed to the coil and rotates with it helps change the direction of the current through the coil so the forces change direction and keep the coil turning DC motor - ANSWER: an electrical device that uses direct current to produce a turning effect; converts electrical energy to mechanical energy Electromagnets are used in? - ANSWER: Cranes, electric bells, circuit- breakers and relays Faraday's law of electromagnetic induction - ANSWER: The EMF induced in a conductor is proportional to the rate at which magnetic field lines are cut by the conductor How can a bar magnet be made? - ANSWER: place a piece of iron or steel inside an electromagnet How can the force on this wire be reversed in direction? - ANSWER: Reverse the current or the magnetic field How to strengthen an electromagnet? - ANSWER: increase electricity (more batteries), increase number of coils, add iron to the core..