Using Ohm's law, if 120 V is applied across 300 ohms, what is the current?

Using Ohm's law, if 120 V is applied across 300 ohms, what is the current?

• A. 40 mA
• B. 120 mA
• C. 400 mA
• D. 2 A

Answer: (C)

Ohm's law links voltage, current, and resistance: current equals voltage divided by resistance. With 120 volts across 300 ohms, the current is 120 / 300 = 0.4 amperes, which is 400 milliamperes. This shows that for a fixed resistance, current scales with voltage. If you changed the voltage, the current would change proportionally (e.g., 12 V across 300 Ω would give about 40 mA, 600 V would give about 2 A).

Ohm's law links voltage, current, and resistance: current equals voltage divided by resistance. With 120 volts across 300 ohms, the current is 120 / 300 = 0.4 amperes, which is 400 milliamperes. This shows that for a fixed resistance, current scales with voltage. If you changed the voltage, the current would change proportionally (e.g., 12 V across 300 Ω would give about 40 mA, 600 V would give about 2 A).