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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), its approximate resistivity is $\left( {{m_e} = 9.1 \times {{10}^{ - 31}}\,kg} \right)$
  • A${10^{ - 5}}\,\Omega m$
  • B${10^{ - 6}}\,\Omega m$
  • C${10^{ - 7}}\,\Omega m$
  • D${10^{ - 8}}\,\Omega m$
JEE MAIN 2019, Medium
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