Question on Ohm's Law?

Double check me.
Assume 12 volts is constant.

If I want to use 4 watts power, would I use a 36 Ohm resistor?
If I want to use 27 watts power, I w ould use a 5.33 Ohm resistor?

Clive Mckraken2012-11-16T07:45:54Z

Favorite Answer

You got it right

billrussell422012-11-16T09:07:38Z

12²/36 = 4 watts
and
12²/5.33 = 27 watts

now that was not very difficult, was it.

Anonymous2012-11-16T09:05:36Z

I really do not understand your question.

The values you give, the resistors would use the 4 and 27 watt.
So how are You going to use 4 or 27 watt if they're already being used?

Maybe I'm being pedantic.

Helmi2012-11-16T08:03:24Z

Basic Formula Ohm's Law :
i) V=IR
ii) P=IV

If P=4W
P=V^2/R
4=12^2/R
R=36ohm

If P=27W
P=V^2/R
27=12^2/R
R=5.333ohm

You're Answer Definitely Correct =)

?2012-11-16T07:51:10Z

P = E^2/R

R = E^2/P = 144/P

...so the values you give are correct.