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BuBbLeS01

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**Power...PLEASE Help...Test THURSDAY!**

I am having a hard time understanding why some power equations for finding the power dissipated by light bulb(s) don't work. I have...

P = IV = I^2R = V^2/R

But for some of the problems these equations are getting me different numbers for each one! I am getting confused and I now don't know when to use which one and I have a test on Thursday! One example...

Two 97 W (114 V) lightbulbs are wired in series, then the combination is connected to a 114 V supply. How much power is dissipated by each bulb?

I found I using P/V = .851 then when I go to find the power the only equation that gets me the right answer is P = V^2/R then divide by 2 = 24.3 W