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Resistance is $\frac{V}{I}$, and we get the unit $\Omega$.

Another unit is $\frac{W}{A^2}$. How do you derive that unit?

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2 Answers 2

up vote 2 down vote accepted

Watts are a unit of power, $P=IV$. considering the units: $$ \frac{[W]}{[A]^2} = \frac{[A][V]}{[A]^2} = \frac{[V]}{[A]} $$ therefore the units are the same.

In general you can determine the units of anything by considering the equations to determine it and substituting all the variables for their units.

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By doing very basic high school math.

If you multipy Volts/Amps by Amps/Amps, you get (Volts Amps)/Amps2 = Watts/Amps2. This really should have been obvious.

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I understand the downvotes are likely for pointing out this was a dumb question. Sometimes we people write dumb questions, and I think they should be called on it. The OP needs to realize that a few seconds thought would have resolved the problem, and others need to see what level is acceptable here. So downvote if you must, but do you really want to see a lot of questions like this? –  Olin Lathrop Apr 28 at 14:33

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