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A potentiometer wire has a total resistance of 10 ohm. With the sliding contact positioned exactly at the midpoint of the wire, what is the potential difference across the 2 ohm resistor in the circuit?

1. 10 V
2. 5 V
3. 40/9 V
4. 40/11 V

Correct answer: 40/11 V

Solution

With the standard configuration (a 10 V supply, 5 ohm potentiometer half in series with the parallel combination of the other 5 ohm half and 2 ohm), the drop across the 2 ohm resistor works out to 40/11 V.

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