Q 12-03-180JEE MainJEE Main 2022 (27 Jul, Shift 1)Medium
A $1$ m long copper wire carries a current of $1$ A. If the cross section of the wire is $2.0\ \text{mm}^2$ and the resistivity of copper is $1.7\times10^{-8}\ \Omega$ m. The force experienced by moving electron in the wire is ______ $\times10^{-23}$ N
(Charge of electron $= 1.6\times10^{-19}$ C)
Numerical value type. Enter your answer.
Answer: 136
Field inside the wire:
$$E = \rho J = 1.7\times10^{-8}\times\frac{1}{2\times10^{-6}} = 8.5\times10^{-3}\ \text{V m}^{-1}$$
$$F = eE = 1.6\times10^{-19}\times8.5\times10^{-3} = 1.36\times10^{-21} = 136\times10^{-23}\ \text{N}$$
Solution by Sreeraj P, M.Sc Physics