AP Physics C E and M 11.5: Equivalent Resistance

Determine the equivalent resistance of resistor combinations and use it to analyze circuit current and potential differences.

[Maximum number: 4]

E\&M.2.
The circuit shown above consists of a source of variable emf $\mathcal{E}$ , an ideal ammeter A, an ideal voltmeter V, a resistor of resistance R, and a sample of wire with resistance r.

(a)

How does the current through the wire sample compare with the current through the resistor R ? It is greater through R. It is greater through the sample. It is the same through both. It depends on the resistance of the sample.
Justify your answer.

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(b)

How does the potential difference across the wire sample compare with the potential difference across the resistor R ? It is greater across R. It is greater across the sample. It is the same across both. It depends on the resistance of the sample.
Justify your answer.
With the sample of wire in place, the emf of the source is set to a given value. The current through and potential difference across the resistor R are measured. This is repeated for several values of emf, and the data are recorded in the table below.

Table for Question (b) — AP Physics C: Electricity & Magnetism

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11.5.A—Describe the equivalent resistance of multiple resistors connected in a circuit question 1

Question (a)

Question (b)