In a circuit with a 9 V battery and a 3 Ω resistor, what is the current?

In a circuit with a 9 V battery and a 3 Ω resistor, what is the current?

• A. 0.33 A
• B. 1 A
• C. 9 A
• D. 3 A

Answer: (D)

Current in a simple circuit is found using Ohm’s law: I = V / R. With a 9-volt source across a 3-ohm resistor, the current is 9 divided by 3, which equals 3 amperes. The units line up as volts per ohm equals amperes, so 3 A is correct. This also shows how changing either voltage or resistance would change the current: higher voltage or lower resistance increases current, while lower voltage or higher resistance decreases it.

Current in a simple circuit is found using Ohm’s law: I = V / R. With a 9-volt source across a 3-ohm resistor, the current is 9 divided by 3, which equals 3 amperes. The units line up as volts per ohm equals amperes, so 3 A is correct. This also shows how changing either voltage or resistance would change the current: higher voltage or lower resistance increases current, while lower voltage or higher resistance decreases it.