What is the resistance of a circuit that draws 0.25 amperes from a 12-volt source?

To find the resistance of this circuit, you need to use Ohm's Law, which states that Resistance equals Voltage divided by Current (R = E / I). The problem gives you a voltage (E) of 12 volts and a current (I) of 0.25 amperes. Plugging these numbers into the formula gives R = 12 / 0.25. Mathematically, dividing by 0.25 (which is one-quarter) is the same as multiplying by 4. Therefore, 12 divided by 0.25 equals 48 ohms. The distractor 3 ohms is incorrect because it is the result of mistakenly multiplying 12 by 0.25, which would calculate power instead of resistance.