Two resistors of 10 Ω and 20 Ω are connected in parallel to a 12 V supply. What is the total current drawn from the source?

• A. 1.2 A
• B. 1.5 A
• C. 2.4 A
• D. 1.8 A

Answer: (D)

In a parallel circuit, the same supply voltage appears across every resistor, and the total current is the sum of the currents through each resistor. Here, each resistor has 12 V across it. The current through the 10 Ω resistor is 12/10 = 1.2 A, and through the 20 Ω resistor it is 12/20 = 0.6 A. Adding these gives a total current from the source of 1.2 + 0.6 = 1.8 A. (Equivalent resistance method also yields Req = 6.67 Ω, and 12/6.67 ≈ 1.8 A.)