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

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

3. 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

4. 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 = A

5. 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

6. End of 4.2.3B – PRACTICE