Need help with these A current of 75.7 mA exists in a metal wire. How many elect

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Need help with these
A current of 75.7 mA exists in a metal wire. How many electrons flow past a given cross-section of the wire in 9.4 min? The fundamental charge is 1.602 Times 10^-19 C. Birds resting on high-voltage power lines are a common sight. A certain copper power line carries a current of 122 A, and its resistance per unit length is 2.39 Times 10^-5 1 Ohm/m. If a bird is standing on this line with its feet 17 cm apart, what is the potential difference across the bird's feet? Answer in units of V.

Explanation / Answer

003) Use equation,

I= dq/dt =(ne)/dt

75.7*10^-3=( n*1.602*10^-19)/(9.4*60)         => n=2.67*10^20

004)

Resistance for 0.17m , R = (2.39*10^-5)*0.17 = 4.063*10^-6 ohm

V=I*R = 122A* 4.063*10^-6 ohm = 0.000496 V = 496 microV

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