Modified by Mr. Wanninkhof What About Watts? 4.2.3B Electrical Power By Mr Wilson Modified by Mr. Wanninkhof

Power Law Moving electrons (current) requires ENERGY How much energy gets used depends on: Strength of push – VOLTAGE Rate of flow – CURRENT

Example #1 A 12 volt battery is connected to a circuit which allows 10 amperes of current to flow. What is the power output of this circuit? P = ? V = 12 V I = 10 A electricity P = IV P = (10 A)(12 V) P = 120 W

Example #2 A 100 watt light bulb is connected to a 120 volt power supply. What amount of current must pass through the light bulb? I = ? V = 120 V P = 100 W electricity P = IV P/ V = IV / V P/V = I I = (100 W) / (120 V) I = 0.833 A

Example #3 A 2.0 ampere current passes through a circuit with a 300 ohm resistance. What is the power generated in this circuit? P = ? I = 2 A R =300 Ω electricity P = I2R P = (2.0 A)2 (300 Ω) P = 1200 W or 1.2 kW

End of 4.2.3B – PRACTICE