Calculating Average Current for a Typical American Family's Electricity Usage

[BuBbLeS01]

Average Current...Simple...

Homework Statement

A typical American family uses 1430 kWh of electricity a month.
What is the average current in the 110 V power line to the house?

Homework Equations

The Attempt at a Solution

Don't I just change kWh to W and divide it by the voltage...
1430 x10^3 = 1430000 / 110 = 13,000A which is def. not right lol.

 

[Tedjn]

Well, [\text{kW}\cdot\text{h}] is not the same thing as a kW, which you can convert to W. Instead, [\text{kW}\cdot\text{h}] is power (kW) multiplied by time (h), which is energy. You have the equation right (i.e. E = iV), but you need to convert to the SI unit of energy, the joule. How would you do that?

 

[BuBbLeS01]

Do 1430x10^3 * 3600s = 5.148x10^9 J

 

[BuBbLeS01]

but what now?

 

[Tedjn]

You had the right idea before with your equation E = iV. You know E, you know V, so you can find i.

 

[BuBbLeS01]

but what is E? Its not measured in J?

 

[Tedjn]

Sorry, that is my mistake. I'm not thinking very clearly today. Power is iV, so you are right to be confused. You know that she uses 1430 kWh in a month. You can find out how many seconds are in a month, and figure out the average power, in kW or W. Then you divide by voltage to find the current.