Question

Find the drift speed of electrons in an iron wire at 30.0 degrees Celsius and of cross section 2.00 x 10^-6 m^2 which carries 5.0 A of current. Compare this speed with the speed of electron gas in the wire.

Answer 1

a)

drift speed, vd=I/n_iron*q*A

=5/(8.5*10^28*1.6*10^-19*2*10^-6)

=1.84*10^-4 m/sec

b)

vrms=sqrt(3kT/me)

=sqrt(3*1.38*10^-23*(273+30)/(9.1*10^-31)

=1.174*10^5 m/sec

==>

Vd/vrms=(1.84*10^-4)/(1.174*10^5)

==> vd/vrms=1.57*10^-9

a)

drift speed, vd=I/n_iron*q*A

=5/(8.5*10^28*1.6*10^-19*2*10^-6)

=1.84*10^-4 m/sec

b)

speed of the electron in gas, vrms=sqrt(3kT/me)

=sqrt(3*1.38*10^-23*(273+30)/(9.1*10^-31)

=1.174*10^5 m/sec

==>

Vd/vrms=(1.84*10^-4)/(1.174*10^5)

==> vd/vrms=1.57*10^-9