What is the strength of the electric field 3.0 cm from a small glass bead that has been charged to + 5.0 nc ?

The electric field produced by a uniformly charged sphere is equal to that produced by a single point charge:

where
is the Coulomb's constant
Q is the charge of the sphere
r is the distance at which we calculate the field strength

The glass bead of our problem has a charge of , and if we use the previous formula we can calculate the electric field strength at distance  from the bead:

It should be d if not then c