Answer: 400 Ω.
- A 40 Ω
- B 100 Ω
- C 200 Ω
- D 400 Ω
Correct answer: D. 400 Ω
Explanation: R = V²/P = 200²/100 = 40000/100 = 400 Ω.
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.