21.2 ElectromagnetismAssessment Questions 1-4

Magnetic reviewhttp://

www.youtube.com/watch?v=uj0DFDfQajw&NR=1&feature=fvwp

1. Besides a magnet what can produce a magnetic field?A moving electric charge can create a

magnetic field = electricity flowing through a wire. LT#2

We use moving magnets to generate an electric current & we use electric current to make magnets.

http://www.youtube.com/watch?v=9Zy0VHBXxLU&annotation_id=annotation_397286&feature=iv

2. How is the magnetic field of an electromagnet controlled?It can be turned on and off LT#2http://

www.youtube.com/watch?v=UBiKruVV3a0It’s strength and direction can be controlled

by controlling the current.http://www.ehow.co.uk/video_4951982_do-ele

ctromagnets-work_.html

3. How are solenoids and electromagnets used in galvanometers, electric motors and loudspeakers?They all change electrical energy into

mechanical energy. LT#1http://

www.youtube.com/watch?v=e5434dDB-7whttp://

www.youtube.com/watch?v=it_Z7NdKgmY&feature=PlayList&p=305357ACC216006C&playnext_from=PL

Galvanometers detect electric current A magnet and a wire coil  are used to

measure a magnetic field caused by current.

Moving a magnet through the coil will deflect the galvanometer = generator effect. LT#3

4. How does a ferromagnetic rod inside a solenoid affect the strength of an electromagnet? LT#2

The rod makes the magnetic field much stronger.

When current flows through the coil, it creates a magnetic field that magnetizes the ferromagnetic rod.