In the circuit shown in Fig. 25.3, a variable resistor R is connected across the
ID: 2146029 • Letter: I
Question
In the circuit shown in Fig. 25.3, a variable resistor R is connected across the terminals of a battery, and an ideal ammeter and ideal voltmeter are also connected. In the figure, ? is the internal emf of the battery, and r is its internal resistance. All the connecting cables have no appreciable resistance. The ammeter reads 3.10 A when the voltmeter reads 5.08 V, and the voltmeter reads 15.0 V when the ammeter reads 0.00 V. In Fig. 25.3, the internal emf of the battery is closest to:
5.08 V
8.18 V
9.92 V
15.0 V
20.1 V
Explanation / Answer
9.92 V