In a conductor, if the number of conduction electrons per unit volume is 8.5 × 10 28    m -…

In a conductor, if the number of conduction electrons per unit volume is 8.5×1028  m-3 and mean free time is 25fs (femto second), it’s approximate resistivity is: me=9.1×10-31kg

 

  1. 10-7Ω m
  2. 10-6Ω m
  3. 10-5Ω m
  4. 10-8Ω m

Solution

We know i=neAvd
i=VR=VAρl=EAρ
ρ=EAi=EAneAvd
Drift velocity can be written as vd=eEmeτ
ρ=EAmeneAeEτ=mene2τ
=9.1×10-318.5×1028×1.6×10-192×25×10-15
1.65×10-8 Ω m

Asked in: JEE Main 2019 (09 Apr Shift 2)

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