When a 20.0-ohm resistor is connected across the terminals of a 12.0-V battery,the voltage across the terminals of the battery falls by 0.300 V.What is the internal resistance of this battery?
A) 3.60 Ω
B) 1.56 Ω
C) 0.98 Ω
D) 0.30 Ω
E) 0.51 Ω

Question

Quizplus · Accepted Answer

The voltage drop across the internal resistance is 0.300 V. Using Ohm's Law (V = IR), the current through the circuit is I = 12.0 V / 20.0 Ω = 0.6 A. The internal resistance r can be found using the voltage drop: 0.300 V = 0.6 A * r, so r = 0.300 V / 0.6 A = 0.50 Ω.

When a 200-Ohm Resistor Is Connected Across the Terminals of a 12