Question

In a conductor, if the number of conduction electrons per unit volume is $8.5 \times 10^{28} \; m^{-3}$ and mean free time is $25\,fs$ (femto second), it's approximate resistivity is :
$(m_e = 9.1 \times 10^{31} \; kg)$

• A. $10^{-5} \Omega m$
• B. $10^{-6} \Omega m$
• C. $10^{-7} \Omega m$
• D. $10^{- 8} \Omega m$

Answer 1

Answer: (D)

$\rho = \frac{m}{ne^2 \tau}$
$ = 1.67 \times 10^{-8} \Omega m $