Power: The resistivity of gold is 2.44 × 10-8 ? ? m at a temperature of 20°C. A gold wire, 1.8 mm in diameter and 14 cm long, carries a current of 480 mA. What power is dissipated in this wire at 20°C?
A. 0.31 mW
B. 0.077 mW
C. 0.14 mW
D. 0.19 mW
E. 0.25 mW
Answer: A
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