Question

In the video, they said that 1kwh is equal to 3.6*109 J

But, in the question and answer, they said that 1 kwh=3.6*106 J.
So, Please tell me which is correct?

Answer 1

1 watt is defined as 1 joule/second. So if you multiply a watt times seconds, you get Ws which is also a joule.

So 1kW is 1000W, and an hour is 60 seconds x 60 minutes.

So 1kWh = 3600kWs = 3,600,000Ws = 3,600,000J

So kWh x 3600sec/hr x 1000W/kW = J

One kilowatt-hour is equal to 3600000 joules:

1kWh = 3600000J = 3.6⋅10⁶J = 3.6MJ

So the energy in joules E_(J) is equal to 3600000 times the energy in kilowatt-hour E_(kWh):

E_(J) = 3600000 ⋅ E_(kWh)