If the magnitude of the electrostatic force felt by a charge is three times that from another charge, but their charges are the same, then the electric field strength of this charge is the strength of the other charge.
three times
nine times
one-third
one-ninth

three times

Explanation:

F=Eq

3F=3Eq

three times

Explanation:

The relation between the force and the electrostatic field is given by

F = q E

where, F be the force , q be the charge and E be the strength of electrostatic field.

Here the charge is q

F = q E (1)

Now the charge remains same but the force three times, let E' be the electrostatic field strength.

3F = q E'     (2)

Divide equation (2) by equation (1)

E' / E = 3F / F

E' = 3 E

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it