May 1, 2014 · The first equation in your first post is this:##P=I^2R## Here you have no variable for ##V##. So you can use ##V=IR## and plug in I and R from the first equation to it and find V. Then you can use ##P=IV##. This is the same as using ##P=I^2R## as I mentioned in my previous post. Then you have ##P=\frac{V^2}{R}##

for finding out power supplied by the battery we use the formula, P = V*I; where V is the voltage across its terminal and I is current flowing out positive terminal. For finding out power consumed by the resistance of wire. we prefer, P = I^2*R; where I is the current flowing through the wire/resistance and R is the resistance offered by the wire.

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But power is actually found using P = VI, and for the case of constant voltage across a resistor (as you mentioned), we would use the I-squared expression (its just easier). Thus, the I-squared expression is merely a convenient way of measuring power in a resistive circuit and is not meant to show any kind of peculiar characteristic or ...

Jun 18, 2016 · However, one of the formulas I've been given to calculate power loss is P=V^2/R, which in this context produces ridiculously high numbers. For example, P=40,000^2/1 (assuming the cable has a resistance of 1 ohm) = 1,600MW. This obviously isn't what happens in reality. So, is the formula only applicable in certain circumstances?

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I can simply say that in the first equation P = V^2/R power is inversely proportional to R because it's in an parallel circuit remember that in a parallel circuit voltage is constant throughout. (And we have V in the equation) And in the second equation P=I^2R.

Aug 9, 2019 · There is one, I=V/R is only valid for resistors, so as a general definition of power it is better to go with P=IV which applies regardless of component. a schematic or an explanation of the actual situation would get you better answers.

Oct 25, 2016 · $$ P = εI $$ where ε is the emf. ε is the energy per unit charge. Current is the charge passing through per unit time. Therefore, the product of them means how much energy is passing through per unit time. You also have the relation between I, ε, R. You can then find the answer you want

Mar 17, 2016 · I think that P=IV is mainly used to find the power of the whole circuit whereas P=I^2R is used to find how much energy is given out by the component per second. But not sure if I am right. OK, that is a good start.