If the magnitude of a charge is half as much as another charge, but the force experienced is the same, then the electric field strength of this charge is the strength of the other charge.

one-fourth
one-half
two times
four times

the electric field strength of this charge is two times the strength of the other charge

Explanation:

Using the relationship between electric field and the charge, which is inversely proportionality. Let the the magnitude of the first charge be Q and the respective electric field be E. It implies that;

E1/E2 = Q2/Q1

E2 = E1 x Q1/Q2

      = E x Q/ (Q/2)

       = 2E