Question

An alternator provides 20 A of peak current at 100 V peak AC to a resistive electric heater. How much heating power is delivered to the load?

Answer 1

-- The resistance of the heater is (volts/current) = 5 ohms

-- The heating (RMS) value of a sinusoidal AC is V(peak)/√2 .  For this particular alternator, V(peak)=100V, so the heating (RMS) equivalent is 70.71 V.

-- The heating power delivered to the electric heater is (E²/R).

Power = (100/√2)² / 5

Power = 5,000 / 5

Power = 1,000 watts