Two identical resistors, each R, connected in parallel. Compared with a single resistor of resistance R, the total resistance is what?

• A. Halved
• B. Doubled
• C. Unchanged
• D. Increased tenfold

Answer: (A)

In parallel, the total resistance drops because the current can split between multiple paths. For two identical resistors, each with resistance R, the combined resistance R_eq satisfies 1/R_eq = 1/R + 1/R = 2/R, so R_eq = R/2. That means the network offers half the opposition to current compared with a single resistor of resistance R. This happens because having two pathways doubles the available routes for current, increasing the total current for the same voltage while keeping each path the same, which reduces the overall resistance. The result is halved.