1. Electric Power

3. Example: Electric Heater An electric heater draws 15.0 A on a 120-V line. How much power does it use and how much does it cost per month (30 days) if it operates 3.0 h per day and the electric company charges 10.5 cents per kWh? (For simplicity, assume current flowing in one direction).

4. Lightning Bolt Typical lightning bolt can transfer 10 9 J of energy across a potential difference of perhaps 5x10 7 V during a time interval of about 0.2 s. Use this information to estimate the total amount of charge transferred, the current, and the average power over the 0.2 s.

5. Power in Household Circuits

6. Will a Fuse Blow? Define the total current drawn by all devices in the circuit shown in the next slide.

8. Alternating Current

10. Average Power

11. Root-Mean-Square Values (RMS)

12. Stereo Power Each channel of stereo receiver is capable of an average power output of 100 W into a 8- W loudspeaker. What is the rms voltage and rms current fed to the speaker at the maximum power of 100 W?