1. Electricity & Magnetism at Work Using Electric Power Chapter 3 Section 3

2. Electric Power The rate at which energy is converted from one form into another. James Watt –1700’s –Designed Steam Engines

3. Power Ratings Stove = 6,000 W Clothes Dryer = 5,400 W Water Heater = 4,500 W Washing Machine = 1,200 W Dishwasher = 1,200 W Hair Dryer = 1,200 W Iron = 1,100 W Microwave = 1,000 W Coffee maker = 1,000 W Toaster = 850 W Food Processor = 500 W Fan = 240 W TV = 100 W Clock radio = 12 W

4. Calculating Power Power = Voltage x Current Watts = Volts x Amps

5. Power Problem A household light bulb has approximately 0.5 amps of current flowing through it. Since the standard household voltage is 120 V, what is the power rating of the light bulb? P = V x A

6. Paying for Energy Energy = Power x TimeKilowatt-hour –kWh ~$0.10 each

7. High Voltage Power 10,000 - 800,000 V –More efficient for long distance conduction House Appliances –Use 120 V

8. Transformers A devise that increases/decreases voltage Primary Wire induces a current onto a secondary wire –Step Up Transformer –Step Down Transformer

9. Hans Christian Oersted 1820 –Electromagnetism Discovers that an electric current creates a magnetic field

10. Michael Faraday & Joseph Henry 1830 –Electric Induction Discover that an electric current can be induced by a changing magnetic field

11. Thomas Edison 1882 –Opens his first DC electric producing power plant in New York City. –It provided 120 V to 2.6 square kilometers of customers.

12. Nikola Tesla 1888 –Received patents for distributing power via high voltage AC, using step up/down transformers

13. Nikola Tesla 1893 –AC is used to power the World’s Fair in Chicago