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This
exhibit uses a special low voltage bulb along with an
ordinary bulb. When they are adjusted to be equally
bright, they use equal amounts of electrical power.
This exhibit teaches the visitor that a watt is a measure
of electric power. One watt equals one volt times one
amp. Different combinations of voltage and currents
give the same power. For instance, electric companies
do not sell electricity, they sell power. This power
is transmitted by means of electricity. The same amount
of power can be delivered by high voltage at a high
current. High voltage increases shock hazards. Electric
power doesn't come to your house at a lower voltage
because large currents cause the wires to heat up, and
the danger of fire is increased. In the U.S., electric
power is delivered to homes at 120 volts. This is to
minimize the danger of fire and shock.
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