An old 9.0-V battery produces a potential difference of 9.0 V when checked with a voltmeter.If the internal resistance is 14.3 Ω and a 100 Ω resistor is connected across the battery leads,what is the voltage across the battery's leads?
A)7.9 V
B)11 V
C)5.4 V
D)9.0 V
E)7.1 V

Question

Quizplus · Accepted Answer

We can use the formula: V = E -(I × r), where V is the voltage across the battery's leads, E is the emf of the battery, I is the current flowing through the circuit, and r is the internal resistance of the battery.

First, we need to find the current flowing through the circuit. We can use Ohm's law: I = V/R, where R is the total resistance of the circuit (R = 100 Ω + 14.3 Ω = 114.3 Ω).

I = V/R = (9.0 V) / (114.3 Ω) = 0.0787 A

Now we can use the formula to find the voltage across the battery's leads:

V = E - (I x r) = 9.0 V - (0.0787 A x 14.3 Ω) = 7.9 V

Therefore, the answer is A) 7.9 V.

An Old 90-V Battery Produces a Potential Difference of 9