Ohm's law application: If a circuit has 12 V and 3 Ω, what is the current?

Ohm's law application: If a circuit has 12 V and 3 Ω, what is the current?

• A. 3 A
• B. 6 A
• C. 9 A
• D. 4 A

Answer: (D)

Current is determined by how much voltage pushes through a given resistance. Ohm's law states I = V / R. With 12 volts across a 3-ohm resistor, the current is 12 ÷ 3 = 4 amperes. This makes sense because increasing voltage (with the same resistance) increases current, while increasing resistance (with the same voltage) decreases current. If you see 3 amperes, that would require a voltage of V = I × R = 3 A × 3 Ω = 9 V, not 12 V. For 6 amperes, you'd need 18 V, and for 9 amperes, 27 V. So 12 V and 3 Ω indeed give 4 A.

Current is determined by how much voltage pushes through a given resistance. Ohm's law states I = V / R. With 12 volts across a 3-ohm resistor, the current is 12 ÷ 3 = 4 amperes. This makes sense because increasing voltage (with the same resistance) increases current, while increasing resistance (with the same voltage) decreases current.

If you see 3 amperes, that would require a voltage of V = I × R = 3 A × 3 Ω = 9 V, not 12 V. For 6 amperes, you'd need 18 V, and for 9 amperes, 27 V. So 12 V and 3 Ω indeed give 4 A.