Consider a conductor of length $40 \ cm$,where a potential difference of $10 \ V$ is maintained between the ends of the conductor. Find out the mobility of the electrons,provided the drift velocity of the electrons is $5 \times 10^{-6} \ m/s$.

• A
  $8 \times 10^{-7} \ m^2 \ V^{-1} \ s^{-1}$
• B
  $2 \times 10^{-7} \ m^2 \ V^{-1} \ s^{-1}$
• C
  $4 \times 10^{-6} \ m^2 \ V^{-1} \ s^{-1}$
• D
  $10^{-7} \ m^2 \ V^{-1} \ s^{-1}$