Question

3. Three charged particles are positioned in the xy plane: a 50-nC charge at y 6 m on the y axis, a -80-nC charge at x4 m on the x axis, and a 70-nc charge at y -6 m on the y axis. (a) What is the electric potential (relative to a zero at infinity) at the point x 8 m on the x axis? (b) What is the electric potential energy of this configuration of charges?

Answer 1

we want to calculate electric potential at point P due to charges at A, B and C. V = V_A + V_B + V_C (1) V_A = 1/4 pi elementof times 70 times 12^9/10 = > V_A = 63 V (2) V_B = 1/4 pi elementof_e times - 20 times 10^-9/12 = -9 times 10^9 times 20 times 10^-9/12 = > V_B = -6.V (3) V_c = 1/4 pi r_e times 50 times 10^-9/10 = > V_c = 45 v (4) Put (2), (3) and (4) in (1), we get, v = 63 - 60 + 45 v = 4 sigma v \r\n work done to bring charge 50 nc at point c W_1 = 0 work done to bring charge - 80 nc at B (Now potential due to gaps at the position of -80 nc play the roles). w_2 = (potential at the position of B due to 50nc) times - 80nc = 1/ 4 pi elementof times 50 times 10^-9/2 squareroot 13