Answer: E + Ir.
- A E - Ir
- B E
- C Ir - E
- D E + Ir
Correct answer: D. E + Ir
Explanation: During charging, current enters the positive terminal of the cell. The applied terminal voltage must overcome both the emf and the internal resistance drop, so V = E + Ir.
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.