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

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