Answer: I 2R.
- A IR
- B I<sup>2R</sup>
- C IR<sup>2</sup>
- D I<sup>2</sup>/R
Correct answer: B. I<sup>2R</sup>
Explanation: P = I<sup>2</sup> R = V<sup>2</sup>/R = IV. All three forms are equivalent. P = I<sup>2</sup> R is most direct.
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.