In a conductor, if the number of conduction electrons per unit volume is 8.5 × 10 28    m - 3 and mean free time is 25   f s (femto second), it’s approximate resistivity is: m e = 9.1 × 10 - 31   k g

Step-by-step solution

We know i = n e Av d ⇒ i = V R = V A ρ l = E A ρ ρ = E A i = E A n e Av d Drift velocity can be written as v d = e E m e τ ρ = E A m e n e A e E τ = m e n e 2 τ = 9.1 × 1 0 - 31 8.5 × 1 0 28 × 1.6 × 10 - 19 2 × 25 × 1 0 - 15 ≈ 1.65 × 1 0 - 8   Ω   m