1. Electric Power Energy Cost
October 4, 2017
Electric Power
Energy Cost

2. Drill - Take out Vocabulary Chart
An electrical appliance draws 18.0 amperes of current when connected to a 150-volt source of potential difference. What is the total amount of power dissipated by this appliance?
How much does your household pay for electricity?
What happens to the amount of energy used by electric devices when you switch from one setting to another?
Is it practical to use electric devices in the lowest setting?

3. Electric Power
Electric Power = rate of converting electric energy into other forms of energy (i.e. heat, light)
P = IV
Power is measured in Watts (1 watt = 1 joule/1 second)
So… P = E/t
“E” is electric energy

4. Electric Energy
Electric Energy = calculated by multiplying power by time.
P = E/t
So… E = Pt
Measured in joules of kWh
Convert power in watts  kilowatts
Multiply by time in hours

5. Cost of Electric Energy
Total cost = (EkWh)(cost/kWh)
Total cost = (Electric energy) x (cost per kWh)

6. Example #1 A television set draws 2.0 A when operated on 120 V.
How much power, in watts, does the set use?
If the set is operated for an average of 7.0 h/day, what energy in kWh does it consume per month (30 days)?
At 11¢ per kWh, what is the cost of operating the set per month?