Answer: r/2.
- A 2r
- B r/2
- C r
- D 4r
Correct answer: B. r/2
Explanation: For two identical internal resistances connected in parallel, the equivalent resistance is r/2. The equivalent emf remains E.
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.