Question

Two point charges, Q1 = 3.2 μC and Q2 = -1.3 μC , 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. At what point(s) along the x axis is the electric field zero? Determine the x-coordinate(s) of the point(s). At what point(s) along the x axis is the potential zero? Determine the x-coordinate(s) of the point(s).

At what point(s) along the xx axis is the electric field zero? Determine the xx-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.

At what point(s) along the xx axis is the potential zero? Determine the xx-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.

Answer 1

82 2 »( 2

Let electric field is zero at point P

r = 6 cm

$\frac{kQ_1}{(r+x)^2} = \frac{kQ_2}{(x)^2} \\$

$\frac{3.2*10^{-6}}{(0.06+x)^2} = \frac{1.3*10^{-6}}{(x)^2} \\$

on solving we get

   x = 0.10546 m = 11 cm

(2) potential will be zero at a point somewhere in between Q1 and Q2. Let potential is zero at a distance x from Q2. So this point is at a distance (r-x) from Q1

$\frac{kQ_1}{(r-x)} = \frac{kQ_2}{(x)} \\ \frac{3.2*10^{-6}}{(0.06-x)} = \frac{1.3*10^{-6}}{(x)} \\$

on solving we get

x = - 0.01733 m = -1.7 cm

===============================================================

mention in comment box in case of any doubt