Q. A battery of $e.m.f.\ E$ and internal resistance $r$ is connected to a variable resistor $R$ as shown here. Which one of the following is true
A) Potential difference across the terminals of the battery is maximum when $R = r$
B) Power delivered to the resistor is maximum when $R = r$
C) Current in the circuit is maximum when $R = r$
D) Current in the circuit is maximum when $R \gg r$
Explanation
(b) For power to be maximum
External resistance = Equivalent internal resistance of the circuit
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.