Three charges are located at 100-m intervals along a horizontal line: a charge of - 3.0 C on the left, 2.0 C in the middle, and 1.0 C on the right. What is the electric field on the horizontal line halfway between the - 3.0 C and 2.0 C charges?

1.84 x 10^7 N/C

Explanation:

Let q 1 = - 3 C, q2 = 2 C, q3 = 1 C

Electric field at P due to q1 is E1, due to q2 is E2 and due to q3 is E3.

E1 = k (3) / (50) ^2 = 9 x 10^9 x 3 / 2500 = 108 x 10^5 N/C

E2 = k (2) / (50) ^2 = 9 x 10^9 x 2 / 2500 = 72 x 10^5 N/C

E3 = k (1) / (150) ^2 = 9 x 10^9 x 1 / 22500 = 4 x 10^5 N/C

Resultant electric field at P is given by

E = E1 + E2 + E3 = (108 + 72 + 4) x 10^5 = 184 x 10^5 = 1.84 x 10^7 N/C