Electromagnetism and Generating Electricity

1. Electromagnetism and Generating Electricity

2. Electricity and Magnetism • Electricity and magnetism are different aspects of a single force: electromagnetism • Electricity = result of charged particles • Magnetism = result of moving electrons in an atom

3. Electricity and Magnetism • Moving electric charge creates a magnetic field. • Magnetic field lines form circles around wire • Right hand rule

4. Electricity and Magnetism • Solenoid – a coil of wire with an electric current (produces magnetic field). • By putting a solenoid around an magnetic metal, you create an electromagnet.

5. Solenoid makes an electromagnet

6. Electricity and Magnetism • Strength of electromagnet depends on • Current • Number of loops • Type of core

7. Electromagnetic Devices • Many devices use electromagnets: • Galvanometer – device that detects and measures electric current • Electric motor – uses an electromagnet to turn an axle. • Loudspeaker – uses changing current to move a magnet back and force to produce sound waves

8. Electric Motor

9. Generating Electricity • Moving a magnet into and out of a coil of wire causes charges in a wire to move. • Electromagnetic induction – process of creating a current by changing a magnetic field

10. Generating Electricity • Moving a magnet into and out of a coil of wire causes charges in a wire to move. • Became Faraday’s Law • Obeys conservation of energy

11. Generating Electricity • Generators are the opposite of motors: convert mechanical energy into electrical energy. • Have wire loops that are rotated between two magnets • Can be either AC or DC

12. Generating Electricity • Transformer – device that increases or decreases the voltage of AC. • Consists of two coils of wire wrapped around opposite sides of a closed iron loop • One side has more loops • More loops = greater voltage • Used to transfer electricity (power plant to homes)

13. Transformer

14. Electromagnetism Foldable • Fold the paper as instructed • Label each section as follows: • For each section, draw the correct figure from the book, including labels and the caption. Galvanometer Electric motor Loudspeaker Generator Step-Up Transformer Step-Down Transformer

15. Electromagnetism Foldable • Galvanometer: Fig 5 on p. 630 (Fig 10 p. 638) • Electric motor: Fig 6 on p. 631 (Fig 11 p. 639) • Loudspeaker: Speaker pic on p. 635 (none) • Generator: Fig 3 on p. 634 (Fig 14 p. 643) • Step-Up Transformer: Fig 7A on p. 638 (Fig 16B p. 645) • Step-Down Transformer: Fig 7B on p. 638 (Fig 16A p. 645)