Resposta :
Dados:
Q = ?
d = 0,5 m = 5.10-¹ m
E = 14,4.10^6 N/C
ko = 9.10^9 N.m²/C²
E = ko.Q/d²
14,4.10^6 = 9.10^9.Q/(5.10-¹)²
14,4.10^6 = 9.10^9.Q/25.10-²
14,4.10^6 = 0,36.10^9.1.10².Q
14,4.10^6 = 0,36.10^11.Q
14,4.10^6/0,36.10^11 = Q
40.10^6.10^-11 = Q
40.10^-5 = Q
4.10^-4 C = Q