How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?

To find the electrical power consumed by a device, you use Ohm's Law for power, which is P = I × E (Power equals Current multiplied by Voltage). This is affectionately known as the "PIE" formula. In this question, you are given a voltage (E) of 12 VDC and a current (I) of 0.2 amperes. Simply multiply the two values together: 12 volts × 0.2 amperes = 2.4 watts. The incorrect answers usually result from basic math errors, such as misplacing the decimal point to get 24 watts or dividing the numbers instead of multiplying them.