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A -3.0 nC charge is on the x-axis at x = -9 cm and a +4.0 nC charge is on the x-axis at x = 15 cm. At what point or points on the y-axis is the electric potential zero. y = _____ cm
♦ Relevant knowledgeThe term “electric potential” is used to describe as the quantity of energy needed to move the charge of a particle from one place to another. The quantity is proportional to the force of the charge as well as its distance from a specific reference , which is determined by a constant k known by the Coulomb constant.
The electric potential is a scalar that is given by:
V = k * q / r
If the net potential at y = 2 cm on the y-axis is zero, then this point (assuming that P) would be zero.
V_net = V1 + V2 = 0
k * q1 / r1 + k * q2 / r2 = 0
k * q2 / r2 = -k * q1 / r1
q2 / r2 = -q1 / r1
Assumption: q1 = -3.0 nC&q2 = 4.0 nC
r1 = distance between P and q1 = sqrt ((-9.0-0.0)2 + (0-d)2) = sqrt (81 + d2)
r2 = distance between P and q2 = sqrt ((19-0),2 +(0-d),2) = sqrt (361 + d,2)
And so it is
4.0 / square foot (361 + d ^ 2) = 3.0 / square foot (81 + d ^ 2)
Square sides
16.0 / (361+ d.2) = 9.0 / (81/ + d.2)
16 * 81 + 16* d 2 = 9.0* 361 + 9.0* d 2
d 2 = [9.0* 361-16 *81] /7.0= 279
d = square feet ([279]) = pm 16.7cm
The potential at that point will be null
y = 16.7 cm & y = -16.7 cm