Answer:
Average speed [tex]v_d=\frac{i}{neA}=\frac{20}{8.5\times 10^{28}\times 1.6\times 10^{-19}\times 7.8\times 10^{-5}}=1.87\times 10^{-5}m/sec[/tex]
Explanation:
We have given current through power i = 20 A
Diameter d = 1 cm = 0.01 m
So radius r = 0.005 m
So area [tex]A=\pi r^2=3.14\times 0.005^2=7.8\times 10^{-5}m^2[/tex]
Charge on electron e = [tex]1.6\times 10^{-19}C[/tex]
We know that current is given by [tex]i=neAv_d[/tex], here n is nuber density of free electron, e is charge on electron, A is area and [tex]v_d[/tex] is average speed
We know that for copper n = [tex]8.5\times 10^{28}per\ m^3[/tex]
So average speed [tex]v_d=\frac{i}{neA}=\frac{20}{8.5\times 10^{28}\times 1.6\times 10^{-19}\times 7.8\times 10^{-5}}=1.87\times 10^{-5}m/sec[/tex]
