Using the formula: E = kQ / d² where E is the electric field, Q is the test charge in coulomb, and d is the distance.
E = kQ / d²
k = 9 x 10^9 N-m²/C²
Q = 6.4 x 10^-5 C
d = 2.5 x 10^-2 m
Substituting the given values to the equation, we have:
E = (9 x 10^9)(6.4 x 10^-5) / (2.5 x 10^-2) ²
Electric field at the test charge is 921600000 N/C
