In a parallel circuit with four branches: A=50 Ω, B=30 Ω, C=30 Ω, D=10 Ω, which branch draws the most current?

• A. Branch A because 50 Ω
• B. Branch B because 30 Ω
• C. Branch D because 10 Ω
• D. Branch C because 30 Ω

Answer: (C)

In a parallel circuit, the same voltage is across every branch, so the current in each branch is I = V/R. This means the branch with the smallest resistance will draw the most current. Here, the resistances are 50, 30, 30, and 10 ohms; the smallest is 10 ohms, so that branch carries the most current. If the supply voltage is V, the currents are proportional to 1/R: I_A = V/50, I_B = V/30, I_C = V/30, I_D = V/10. Since V/10 is the largest, the 10-ohm branch draws the most current. The other branches have smaller currents because their higher resistances limit current more.