You buy an 1700W electric tea kettle while on a study abroad program in Britain, where electricity is delivered to homes at 220V. If you use the tea kettle at home in the United States, where electricity is delivered to homes at 120V, how much power will it consume?

This is how NOT to do it:

1700 = 220(current)
current = 7.727 A

P = 7.727(120) = 927.3 W

Why is that incorrect? What is the correct way to do this?

Additional Reference Information

One Response to “How do you analyze power consumption? Is current constant? (Physics problem follows.)?”