Answer:
0.002638 C or 2.6388*10^-3 C
Explanation:
Given that
Quantity of the charge, q = -0.0005 C
Force on the charge of magnitude, F1 = 19 N
Distance from the second charge, r = 25 m
Magnitude of force of the second charge, q2 = ? N
F = (kq1q2) / r², where
k = 9*10^9
19 = (9*10^9 * 0.0005 * q2) / 25²
19 * 625 = 4.5*10^6 * q2
q2 = 11875 / 4.5*10^6
q2 = 0.002638 C or 2.6388*10^-3 C
Thus, the magnitude of the second charge is 0.002638 C or 2.6388*10^-3 C
