A real battery can be modeled as an ideal emf source in series with an internal resistance
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A real battery can be modeled as an ideal emf source E=12.0V in series with an internal resistance r=0.50Ω. The battery is connected to the external circuit described below.
• Resistors R1=2.0Ω and R2=3.0Ω are connected in parallel.
• That parallel combination is connected in series with resistor R3=4.0Ω.
Treat all connecting wires as having negligible resistance.
(a) Determine the equivalent resistance of the external circuit (the combination of R1,R2, and R3).
(b) Calculate the current leaving the battery.
(c) Find the terminal potential difference (the potential difference measured across the battery’s terminals).
(d) Determine the potential difference across R1 and the current through R1.
(e) Express the percentage of the battery’s emf that is lost across its internal resistance when the circuit is operating, and briefly comment on the practical significance of that energy loss.