Thank you for reporting, we will resolve it shortly
Q.
A copper rod $AB$ of length $l$ is rotated about end A with a constant angular velocity $\omega$. The electric field at a distance $x$ from the axis of
rotation is
We know in circular motion net force acting on it must be $\frac{ mv ^{2}}{ r }$
When the rod rotates, electrons in it also rotates which produce electric field $E$ at distance $x$.
Force on the electron, $Fe = eE = m \omega^{2} x$
$\therefore Ee =\frac{ mv ^{2}}{ x } \quad( v = x \omega) $
$ Ee =\frac{ m ( x \omega)^{2}}{ x }$
$ \Rightarrow E =\frac{ m \omega^{2} x }{ e }$