In a parallel arrangement of a 6 Ω resistor across a 12 V supply, what is the current through the 6 Ω resistor?

• A. 2 A
• B. 0.5 A
• C. 3 A
• D. 6 A

Answer: (A)

When a resistor is connected across a constant voltage, the current through it follows Ohm’s law: I = V/R. In a parallel arrangement, each branch has the full supply voltage across it, so the 6 Ω resistor has 12 V across it. The current through that resistor is 12 V divided by 6 Ω, which equals 2 A. So this branch draws 2 amperes from the supply. If there were other parallel branches, they would draw their own currents and the total current from the supply would be the sum of all branches.