Charge q_1 = -1.5 nC is located at the coordinate system origin, while charge q_
ID: 585453 • Letter: C
Question
Charge q_1 = -1.5 nC is located at the coordinate system origin, while charge q_2 = 2.32 nC is located at (a, 0), where a = 0.95 m The point P has coordmates (a. b). where b = 0.85 m. A third charge q_3 = 1.5 nC will be placed later. q_1 = -1.5 nC q_2 = 2.32 nC a = 0.95 m b = 0.85 m q_3 = 1.5 nC How much work W, in joules, would you have to do to bring the third charge, q^3, from very far away to the point P? What is the total potential energy U, in joules, of the final configuration of three charges?Explanation / Answer
Here,
a) q1 - -1.5 nC
q2 = 2.32 nC
a= 0.95 m
b = 0.85 m
q3 = 1.5 nC
a) potential at point P
VP = k * q1/sqrt(a^2 + b^2) + k * q2/b
VP = 9*10^9 * 1 *10^-9 * (-1.5/sqrt(0.95^2 + 0.85^2) + 2.32/0.85)
VP = 14 V
work required for moving the third charge = q3 * VP
work required for moving the third charge = 1.5 *10^-9 * 14 J
work required for moving the third charge = 2.1 *10^-8 J
the work required for moving the third charge is 2.1 *10^-8 J
b)
for the potential energy of sytem = work done for q3 + k * q1 * q2/b
the potential energy of sytem = 2.1 *10^-8 - 9*10^9 * 1.5 *10^-9 * 2.32 *10^-9/.85
solving
the potential energy of sytem = -1.58 *10^-8 J