What is the force felt by the electrons and the nuclei in the rod when the external field described in the problem introduction is applied? (ignore internal fields in the rod for the moment.)a) both electrons and nuclei experience a force to the right.
b) the nuclei experience a force to the right and the electrons experience a force to the left.
c) the electrons experience a force to the left but the nuclei experience no force.
d) the electrons experience no force but the nuclei experience a force to the right.

(B). nuclie experiences a force to the right and electron experiences a force to the left.

Explanation: The nuclie is positively charged and so it will experience a force in the same direction as the direction of the Electric Field {in this case to the right}

On the otherhand, the electrons which are negatively charge will experience a force in opposite direction to that experienced by the nuclie which is positively charged. So the electron experiences a force to the left.

I believe this is clear.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach