please help me with this Exercise 25.12 Part A A copper wire has a square cross

Question

please help me with this

Exercise 25.12 Part A A copper wire has a square cross section 2.8 mm on a side. The wire is 4.5 m long and carries a current of 3.6 A. The density of free electrons is 8.5 x 1028 m 3 Find the magnitude of the current density in the wire Express your answer using two significant figures A/ Submit My Answers Give Up Part B Find the magnitude of the electric field in the wire Express your answer using two significant figures Submit My Answers Give Up Part C How much time is required for an electron to travel the length of the wire? Express your answer using two significant figures Submit My Answers Give Up

Explanation / Answer

Here ,

part A)

current density = I/area
current density = 3.6/(0.0028^2)
current density = 4.59 *10^5 A/m^2

part B)

electric field , E = J * p

E = 4.59 *10^5 * 1.68 *10^-8 V/m

E = 7.71 *10^-3 V/m

part c)

drift speed of electron = J/(n * q)

drift speed of electron = 4.59 *10^5/(1.602 *10^-19 * 8.5 *10^28)

drift speed of electron = 3.37 *10^-5 m/s

time taken = 4.5/(3.37 *10^-5)

time taken = 1.34 *10^5 s

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