798_Physics ProblemsTechnical Physics

798_Physics ProblemsTechnical Physics - 138 Direct Current...

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138 Direct Current Circuits P28.18 (a) VI R = : 33 0 11 0 1 .. V = I af 33 0 22 0 2 = I I 3 300 = . A I 2 150 = A P = IR 2 : 1 2 110 = A a f a f 2 2 220 = a f a f 1 99 0 = . W 2 49 5 = The 11.0- resistor uses more power. (b) PP 12 148 += W == = IV a f a fa f 450 330 148 W FIG. P28.18(a) (c) RRR s =+= + = 11 0 22 0 33 0 ... ΩΩΩ R = : 33 0 33 0 = I , so I = 100 A = 2 : 1 2 = a f a f 2 2 = a f a f 1 11 0 = 2 22 0 = The 22.0- resistor uses more power. FIG. P28.18(c) (d) 2 2 330 + = = IR R bg W = a f a f . V W (e) The parallel configuration uses more power. *P28.19 (a) The resistors 2, 3, and 4 can be combined to a single 2 R resistor. This is in series with resistor 1, with resistance R , so the equivalent resistance of the whole circuit is 3 R . In series, potential difference is shared in proportion to the resistance, so resistor 1 gets 1 3 of the battery voltage and the 2-3-4 parallel combination get 2 3 of the battery voltage. This is the potential difference across resistor 4, but resistors 2 and 3 must share this voltage. 1 3 goes to 2 and 2 3 to 3. The ranking by potential difference is ∆∆∆∆ VVVV 4312 >>> . (b) Based on the reasoning above the potential differences are
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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