How many watts of electrical power are consumed if 400 VDC is supplied to an 800-ohm load?

To find the power consumed by this circuit, you can use the power formula derived directly from Ohm's Law: P = E^2 / R, where P is power in watts, E is voltage in volts, and R is resistance in ohms. First, square the voltage: 400 * 400 = 160,000. Next, divide that result by the resistance: 160,000 / 800 = 200. Therefore, the power consumed is 200 watts. Alternatively, you could first find the current using Ohm's Law (I = E / R), which is 400 / 800 = 0.5 amps. Then, calculate power using P = I * E (0.5 * 400 = 200 watts). The distractor "0.5 watts" is a trap for those who correctly calculate the current but forget to multiply it by the voltage to find power.