In the same parallel circuit, what is the current through the 3 Ω resistor?

In the same parallel circuit, what is the current through the 3 Ω resistor?

• A. 80 A
• B. 40 A
• C. 20 A
• D. 60 A

Answer: (B)

In a parallel circuit, the voltage across every branch equals the source voltage, and the current through a branch is found with I = V/R. If the parallel network has 120 V across it, the 3 Ω resistor carries I = 120 V / 3 Ω = 40 A. The other currents would require different voltages across that same resistor, which isn’t the case in a single parallel network, so 40 A is the correct current.

In a parallel circuit, the voltage across every branch equals the source voltage, and the current through a branch is found with I = V/R. If the parallel network has 120 V across it, the 3 Ω resistor carries I = 120 V / 3 Ω = 40 A. The other currents would require different voltages across that same resistor, which isn’t the case in a single parallel network, so 40 A is the correct current.