What is the peak current through a 500-W room heater that operates on 120-V AC power?

Video Transcript

This is College Physics Answers with Shaun Dychko. A 500 watt room heater is operating with 120 volts. Now we have to assume that this is an rms voltage as it is for a North-American outlet. So when we are finding the peak current, we can first find the rms current by using this formula that the power is the product of the rms current and the rms voltage; find a formula for the rms current by dividing both sides by V rms and then we get that rms current is the power divided by the rms voltage and then we also know that the rms current is the peak current divided by square root 2 and we can solve this for I naught by multiplying both sides square root 2. So the peak current then is the rms current times square root 2 and the rms current is power divided by rms voltage. So that's 500 watts divided by 120 volts times square root 2 which is 5.89 amps is the peak current.