Physics · 2019
JEE Main · 9 April 2019, Shift 2 · Q17
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…
In a conductor, if the number of conduction electrons per unit volume is $\displaystyle 8.5 \times 10^{28} \mathrm{~m}^{-3}$ and mean free time is $\displaystyle 25 f s$ (femto second), it's approximate resistivity is :
$$\left(\mathrm{m}_{\mathrm{e}}=9.1 \times 10^{-31} \mathrm{~kg}\right)
$$
Official answer
(4)
$\displaystyle 10^{-8} \Omega \mathrm{~m}$
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JEE Main 2019 Physics question, with the answer from NTA’s final answer key. Where our answers come from.