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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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closed as off-topic by DavePhD, Kyle Kanos, Brandon Enright, Qmechanic Apr 30 '14 at 12:29

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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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