21.2 Electromagnetism

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# 21.2 Electromagnetism - PowerPoint PPT Presentation

21.2 Electromagnetism. Assessment Questions 1 -4. Magnetic review. http:// 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

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## 21.2 Electromagnetism

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Presentation Transcript
1. 21.2 Electromagnetism Assessment Questions 1-4

3. 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

4. 2. How is the magnetic field of an electromagnet controlled? • It can be turned on and off LT#2 • http://www.youtube.com/watch?v=UBiKruVV3a0 • It’s strength and direction can be controlled by controlling the current. • http://www.ehow.co.uk/video_4951982_do-electromagnets-work_.html

5. 3. How are solenoids and electromagnets used in galvanometers, electric motors and loudspeakers? • They all change electrical energy into mechanical energy. LT#1 • http://www.youtube.com/watch?v=e5434dDB-7w • http://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.

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

7. 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.