253-hwk-28b

253-hwk-28b - 240 C , then how long will they last if the...

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HPHY 253 Homework 28b Direct-Current Circuits Dr. A. E. Bak Name 28 : 16 . The ammeter shown in Figure P 28 : 16 reads 2 : 00 A . Find I 1 , I 2 , and E . 28 : 17 . Determine the current in each branch of the circuit shown in Figure P 28 : 17 . 28 : 23 . In the circuit of Figure P 28 : 23 , determine the current in each resistor and the potential di/erence across the 200 - resistor. 28 : 37 . An electric heater is rated at 1500 W , a toaster at 750 W , and an electric grill at 1000 W . The three appliances are connected to a common 120 - V household circuit. (a) How much current does each appliance draw? (b) Is a circuit with a 25 : 0 - A circuit breaker su¢ cient in this situation? Explain your answer. 28 : 41 . Four 1 : 50 - V AA batteries in series are used to power a transistor radio. If the batteries can provide a total charge of
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Unformatted text preview: 240 C , then how long will they last if the radio has a resistance of 200 & ? 6. Serway & Jewett Problem 28 : 43 . Calculate the potential di/erence between points a and b in Figure P 28 : 43 and identify which point is at the higher potential. 7. A voltage source supplies a current I to a parallel combination of resistances R 1 and R 2 . (a) Show that I 1 = IR 2 R 1 + R 2 ; I 2 = IR 1 R 1 + R 2 are the currents in the respective resistors. (b) A copper wire of radius : 250 mm has an aluminum jacket of outer radius : 380 mm . There is a 2 : 00-A current in the composite wire. Calculate the current in each material. In order to calcu-late the necessary resistances, make use of the Table 27 : 2 entitled Resistivities and Temperature Coe cients of Resistivity for Various Materials . 1...
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This note was uploaded on 05/01/2011 for the course HPHY 253 taught by Professor Bak during the Spring '09 term at Morehouse.

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