Answer: R/4.
- A R/4
- B R/2
- C R
- D 2R
Correct answer: A. R/4
Explanation: The two halves are each R/2 and are in parallel. R<sub>eq</sub> = (R/2)(R/2)/(R/2+R/2) = (R<sup>2</sup>/4)/R = R/4.
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.