Currents up to 10 A can be carried by a 14-guage copper wire. a) What is the res

Question

Currents up to 10 A can be carried by a 14-guage copper wire. a) What is the resistance of 100 m of 14-guage wire? b) What is the current density when the current is 10 A? c) What is the electric field in the wire when the current is 10 A? d) How long does it take for an electron to travel 100m in the wire when the current is 10 A? (assume that for copper ? = 1.7*10^(-8)?*m, n = 8.47*10^(28) atoms/m^(3))

14-guage Wire:

Diameter in mm = 1.626

Area, mm^2 = 2.081

Note: This is a basic electic physics class. The more simple the answer, the better. Just stick to the basics.

Explanation / Answer

a)Resistance =rho*l/A =1.7*10^(-8) ohm*m *100/(2.081*10^-9) =816.91 ohm (ans)

b)Current Density =I/A=10/(2.081*10^-9) =4.80*10^9 A/m^2 (ans)

c)Electric Field =The E-field in the interior of a conductor is always 0, because charges in it are free to move, and will position themselves so as to cancel any E-field inside the conductor

d)drift velocity,Vd=J/nq= 4.80*10^9 A/m^2/[8.47*10^(28)*1.6*10^(-19) ]=0.354 m/sec

Time taken =L/Vd =10/0.354 =28.25 sec (ans)

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