In a DC motor circuit, a 12-volt battery delivers 10 amperes to the motor. What resistance is required to provide exactly 10 A?

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Multiple Choice

In a DC motor circuit, a 12-volt battery delivers 10 amperes to the motor. What resistance is required to provide exactly 10 A?

Ohm's law shows how voltage, current, and resistance relate in a circuit. To get a specific current from a given voltage, you divide the voltage by the current to find the required resistance: R = V / I. Here, with 12 V and a desired 10 A, the needed resistance is 12 / 10 = 1.2 ohms. That’s why 1.2 ohms is the correct choice. If you plugged in the other values with the same 12 V, you’d get different currents: for example, 0.12 ohms would yield about 100 A, 12 ohms would yield about 1 A, and 120 ohms would yield about 0.1 A. In real motors, current can be affected by back-EMF as the motor spins, but for this calculation we’re applying Ohm’s law directly to the given conditions.

Ohm's law shows how voltage, current, and resistance relate in a circuit. To get a specific current from a given voltage, you divide the voltage by the current to find the required resistance: R = V / I. Here, with 12 V and a desired 10 A, the needed resistance is 12 / 10 = 1.2 ohms. That’s why 1.2 ohms is the correct choice. If you plugged in the other values with the same 12 V, you’d get different currents: for example, 0.12 ohms would yield about 100 A, 12 ohms would yield about 1 A, and 120 ohms would yield about 0.1 A. In real motors, current can be affected by back-EMF as the motor spins, but for this calculation we’re applying Ohm’s law directly to the given conditions.

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