Why is power rated in watts if not watts per hour?

[Pengwuino]

I thought watts was defined as J/sec . So how can something be rated in watts/hour? Doesnt that mean Joules per second per hour?

 

[russ_watters]

Where are you seeing this? You sure it isn't watt-hours (w * h)? A watt-hour is a joule per second of power - for an hour.

 

[cepheid]

I've never heard of anything rated in W/hr. Your electricity meter shows your energy consumption in kWh (kilowatt hours), which would be Jh/s. So clearly one kWh = 3600 J (I hope I did that right). Are you sure the Watts and hours were not being multiplied in the example you saw?

edit: russ was quicker on the draw.

 

[Pengwuino]

I thought like, your electricity bill is measured in KW/H... is it suppose to be KW*h?? I don't have it written down anywhere, i just always remembered electricity as being generated as KW/H... have i just been living with a bad assumption for these past few years lol

 

[Pengwuino]

lol oh man, so I've been remembering and writing it down incorrectly? lol oh man... I am an idiot.

So 1 KWh, the thing your billed for... is 3.6MJ?

 

[chroot]

Yes, your bill is measured in kilowatts*hours, not kilowatts/hours.

http://www.google.com/search?hl=en&q=1+kilowatt+*+1+hour+in+joules&btnG=Google+Search

- Warren

 

[cepheid]

And it seems I forgot about the "kilo" in my post

 

[Pengwuino]

Ah beautiful, now my calculations will make more sense.

 

[dextercioby]

There's no physical quantity which would have the (SI) units $\frac{\mbox{W}}{\mbox{s}}$.It would be the rate of variation of power (electrical or mechanical) in unit time,but no one asserted a name to it.

Daniel.