Unformatted text preview: Energy and Power Power
Power • Most appliances have a
label listing the # of watts
(or kilowatts). Voltage (volts) P=V I
• A watt (W) is a unit of power. Power is the rate at which
energy is flowing.
• 1 watt = 1 Joule per second.
watt Current (amps)
Power (watts) Ex: A 100 W light bulb uses 100 Joules of energy every second.
Ex: How can you get more power?
Standard outlets are 120 V
Standard Increase current
Gauge of wire
Gauge Watts and kilowatts
Remember metric conversions?
Our base unit: watt
Kilo means ____________
Therefore, a kilowatt is
A 1500 watt toaster oven is the same
as a _______kilowatt toaster oven.
as 1 Kilowatt-hour (Unit of Energy!)
You buy electricity by the kilowatt-hour
Means 1 kilowatt of power used for 1
At your home, a meter measures kW⋅h
used. A meter reader visits once a month
to obtain the reading.
Your electric bill is based on that kW⋅h
reading! Estimating your electrical charges
The 1050 W means how
many watts used.
Typical charge is 14 ¢ /
Problem: The coffee maker is on for one hour each day. How
much will it cost to run per month? Average watt usage on
If you add up all of
the appliances you
use, you can estimate
how much your
electric bill will be. 2 ...
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