A copper wire of length 1 ~m and uniform cross-sectional area 5 10⁻⁷ ~m ² carries a current of 1 ~A . Assuming that, there are 8 10²⁸ free electrons per m ³ in copper, how long will an electron take to drift from one end of the wire to the other?

Step-by-step solution

Given, l=1 ~m aligned &A=5 10⁻⁷ ~m ² &I=1 ~A &n=8 10²⁸ electrons / m ³ aligned Time taken by an electron to take the drift from one end to the other is given as T= l v_ d ...(i) where, v_ d is the drift velocity. As, v_ d = I n e A = 1 8 10²⁸ 1.6 10⁻¹⁹ 5 10⁻⁷ = 1 6.4 10³ So, substituting the given values in Eq. (i), we get T= 1 1 6.4 10³ =6.4 10³ ~s