1. Energy and Power

2. Energy The ability to do work. Measured in Joules.

3. Electrical Energy Electrical energy results from the flow of an electrical charge. It is usually more convenient to think of electricity in terms of power, which is the rate at which it flows, or the rate at which electrical energy is converted into another form (mechanical energy, heat, light, etc)

4. Power This gives the possibly more familiar unit of the watt. One watt is equivalent to one joule per second.

5. Power When looking at devices in you home, the amount of power used is equal to current times voltage. Electric power=current X voltage

6. Current Electrical charge is labeled coulombs Current is the flow of electrical charge Measured in amperes (coulomb/second)

7. Voltage Voltage is the electric potential energy per charge Measured in Volts (one joule of energy per coulomb)

8. Sample Problem Electric power=current X voltage Sara’s reading lamp draws 1.05 amps when plugged into the 120V line in her house. How much power is the lamp using?

9. Sample Problem Sara’s reading lamp uses 1.05 amps when plugged into the 120V line in her house. How much power is the lamp using? How many kilowatts is that equal to?

10. Sample Problem Sara’s reading lamp uses 1.05 amps when plugged into the 120V line in her house. How much power is the lamp using? If she runs the lamp on average 2 hours each day, what is her usage in kilowatt hours?

11. Sample Problem Sara’s reading lamp uses 1.05 amps when plugged into the 120V line in her house. How much power is the lamp using? If her electrical company charges $0.12 per kilowatt hour, how much will she pay to run her lamp for a year?