P28_034 - 34. The voltage difference across R is VR = E R...

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Unformatted text preview: 34. The voltage difference across R is VR = E R /(R + 2.00 Ω), where R = (5.00 ΩR)/(5.00 Ω + R). Thus, ER R + 2.00 Ω 2 = 2 VR 1 = R R = PR E2 (2.00 Ω)(5.00 Ω + R) 1+ R (5.00 Ω)R = E 1 + 2.00 Ω/R 1 R −2 ≡ 2 E2 f (R ) where we use the equivalence symbol ≡ to define the expression f (R). To maximize PR we need to minimize the expression f (R). We set df (R) 49 4.00 Ω2 + =− =0 2 dR R 25 to obtain R = (4.00 Ω2 )(25)/49 = 1.43 Ω. ...
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This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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