Guy's I am a crazy with embarrassment but here goes: An electric heater is rated for 2400 watts at 240 volts. What power is consumed when the heater is operated at 120 volts? I=P/E, R=E/I, I=E/R, P=EI, I know the steps but with unequal voltages?? man I am so stumped, I know the answer it's (600) but don't know the formula Ohms law out the window to a point what am I missing?

Watts = Amps times Volts Volts = Amps times Ohms therefore .. Watts = Amps times amps times Ohms so ... amps times amps is a 'squared' relationship that is, reducing the volts by half, and you cut the amps by four (2x2). Thus, 1/4th the heat.