... sau a) a= 15 cm, x= 20 cm q 1 = q 2 = 2,5 .10 -6 C, q 3 = 4 .10 -6 C b) q 1 = 6,25 .10 -6 C, q 2 = -6,25 .10 -6 C, q 3 = 5 .10 -6 C a= 15 cm, x= 20 cm c) a= 15 cm, x= 20 cm q 1 = q 3 = 2,5 .10 -6 C , ... 30 cm; q 1 = q 2 = q 3 = 5 .10 -6 C 3 b) a= 30 cm; q 1 = q 3 = 5 .10 -6 C , q 2 = -5 .10 -6 C c) a= 20 cm; q 1 = q 3 = 4 .10 -6 C , q 2 = 2 .10 -6 C d) a= 20 cm; q 1 = 4 .10 -6 C, q 2 = -2 .10 -6 C, ... 5 .10 -6 C d) a= 15 cm, x= 20 cm q 1 = q 3 = 2,5 .10 -6 C , q 2 = -5 .10 -6 C e) a= 6 cm, x= 4 cm q 1 = q 3 = 2,5 .10 -6 C , q 2 = 5 .10 -6 C f) a= 6 cm, x= 4 cm q 1 = q 3 = 5 .10 -6 C , q 2 = -2,5 .10 ...