Chapter 4: Q18E (page 842)
What diameter must a copper wire have if its resistance is to be the same as that of an equal length of aluminium wire with diameter 2.14mm?
Short Answer
The diameter of the copper wire must be 1.69mm.
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Chapter 4: Q18E (page 842)
What diameter must a copper wire have if its resistance is to be the same as that of an equal length of aluminium wire with diameter 2.14mm?
The diameter of the copper wire must be 1.69mm.
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Question: In the circuit shown in Fig. E26.49, C = 5.90 mF, 詯 = 28.0 V, and the emf has negligible resistance. Initially, the capacitor is uncharged and the switch S is in position 1. The switch is then moved to position 2 so that the capacitor begins to charge. (a) What will be the charge on the capacitor a long time after S is moved to position 2? (b) After S has been in position 2 for 3.00 ms, the charge on the capacitor is measured to be 110 mC What is the value of the resistance R? (c) How long after S is moved to position 2 will the charge on the capacitor be equal to 99.0% of the final value found in part (a)?

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A 5.00-A current runs through a 12-gauge copper wire (diameter
2.05 mm) and through a light bulb. Copper hasfree electrons per
cubic meter. (a) How many electrons pass through the light bulb each
second? (b) What is the current density in the wire? (c) At what speed does
a typical electron pass by any given point in the wire? (d) If you were to use
wire of twice the diameter, which of the above answers would change?
Would they increase or decrease?
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