Two point charges, Q1 = 2.9 C and Q2 = -1.3 C , are placed on the x axis. Suppos
ID: 1501928 • Letter: T
Question
Two point charges, Q1 = 2.9 C and Q2 = -1.3 C , are placed on the x axis. Suppose that Q2 is placed at the origin, and Q1 is placed at the coordinate x1 = 6.0 cm
A)At what point(s) along the x axis is the electric field zero? Determine the x-coordinate(s) of the point(s).
B)At what point(s) along the x axis is the potential zero? Determine the x-coordinate(s) of the point(s).
Express your answer using two significant figures. If there is more than one answer, enter your answers in ascending order separated by commas.
Explanation / Answer
let at point x on +x axis the total electric field = 0
E1 - E2 = 0
E1 = E2
k*q1/(6+x)^2 = k*q2/x^2
2.9*10^-6/(6+x)^2 = 1.3*10^-6/x^2
(6+x)^2/^2 = 2.9/1.3
(6+x) / x = sqrt(2.9/1.3) = 1.5
6/x + 1 = 1.49
6/x = 0.49
x = 6/0.49 = 12.2 cm
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part B
at point on +x axis
total potential Vtot = 0
V1 + V2 = 0
k*q1/(6+x) + k*q2/x = 0
2.9*10^-6/(6 + x ) - 1.3*10^-6/x = 0
x = 4.875 cm
at point -x
V1 + V2 = 0
k*q1/(6 -x) + k*q2/x = 0
2.9*10^-6/(6 - x ) - 1.3*10^-6/x = 0
x = 1.86 cm
x = -1.86 cm
x = +4.875 cm
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