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E10: Ohm’s “Law”
Materials:
Resistors, ammeter, voltmeter, power supply, wires, switch
Initial definitions and givens:
Resistance:
the resistance of part of a circuit is
defined
to be the ratio of the
voltage across it divided by the current flowing through it.
R (ohms) = V (volts)/I (amperes)
This is not Ohm’s “law”, it a definition
A resistor is said to “obey Ohm’s law” if R doesn’t change when V is changed.
Resistor:
a circuit part with a well-defined resistance.
Initial Instructions and questions:
1. Make a circuit with the power supply, ammeter, switch, and one of the resistors in
series.
Place the voltmeter in parallel with the resistor to measure the voltage
between its two ends. Vary the output of the power supply so that the voltage across
the resistor reads 1, 2, 3, 4, and 6 volts.
Record the current through the resistor at
each setting.
Enter the data in GA and plot.
(Careful:

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