Answer: Load resistance >> source resistance.
- A Load resistance = source internal resistance
- B Load resistance >> source resistance
- C Load resistance << source resistance
- D Temperature is minimum
Correct answer: B. Load resistance >> source resistance
Explanation: Efficiency eta = R<sub>load</sub>/(R<sub>load</sub> + r). This approaches 1 (100%) as R<sub>load</sub> >> r. Maximum efficiency (not maximum power) needs high R<sub>load</sub>.
In series, the same current flows through both resistors; in parallel, the current splits between branches and the voltage across each resistor is the same.
Concept context
Ohm's law, resistors, Kirchhoff's laws, Wheatstone bridge, and cells.