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

c) up is the direction the magnetic force is acting on the charge.