Minimum electric field to lift a small metal ball

Can someone explain to me how to solve this?

A small metal ball of mass 3 grams is charged with 10 microCoulombs. A constant uniform electric field is generated in order to suspend the ball in air. What is the minimum field required to achieve this?

For it to be suspended, there must be no net force on the ball. The two forces acting on the ball are the electrostatic repulsion from the electric field pushing it up, and gravity pushing it down. If there is no net force, these two must be equal.

The force from an electric field on a point particle can be described by

F=q*E

and gravity, as i'm sure you know is

F=m*g

Set the two equal and solve for E

qE=m*g

E=mg/q

The masses of the line and the mechanism are supposed to be very small ... If the field quantum (which is what the photon is for the electromagnetic field) has .... Nothing, having no mass, is certainly lighter than air, so would that cause lift, just like with helium? ... Suppose you are not walking and throw a ball straight up.