Question

Two point charges, Q1 = 3.7?C and Q2 = -1.7?C ,are placed on the x axis. Suppose that Q2 is placed at the origin, and Q1 is placed at the coordinatex1 = ? 4.0cm

Part A

At what point(s) along the x axis is the electric field 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.

Part 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.

Answer 1

1) electric field will be zero at 1 point which is in right of Q2.

for point in the right which is at a distance r from Q2.

kQ2/r^2=KQ1/(r+4)^2

Solving this r= 8.416 cm right of Q2. i.e x=8.416 cm.

2) potential will be zero at 2 points one in the right of Q2 and other in between Q1 and Q2.

For point in the right of Q2 which is at a distance r from Q2.

kQ2/r=kQ1/(4+r)

r=3.4 cm. So, x=3.4cm.

For point in between Q1 and Q2 which is at a distance r left from Q2.

kQ2/r=kQ1/(4-r)

r=1.3 cm So x=-1.3cm