00:01
For this problem on the topic of ac circuits, we are told that the standard voltage in europe is 200 volts, 240 volts rms at 60 hertz.
00:10
If a 5 watt electric razor is taken from the usa to rome and plugged into a receptacle, we want to know the power it will draw in rome, then the rms current that will run through the razor in the united states and then in rome.
00:26
And we want to know if the razor is in danger of being damaged in rome without an adapter.
00:32
We then want to know if the razor is to be used in rome without it being damaged, the type of transformer that would be needed, and we want to then find the resistance of the razor.
00:45
Now the resistance of the razor in usa is equal to the resistance of the razor in rome.
00:54
The resistance doesn't change, and so that means that the rms voltage, vr rms squared in the usa divided by the power drawn in the usa is equal to the rms voltage squared in rome divided by the power that the razor will draw in rome and so by rearranging this equation we get the power that is drawn in rome to be the rms voltage squared in rome divided by the rms voltage in the us squared, all multiplied by the power drawn in the usa.
01:56
And putting our values in, this is 240 volts divided by 120 volts squared times a power of 5 watts...