Question

Two charges are placed on the x-axis. A charge q1= 6µC is placed at x=3cm and charge

q2=-12µC charge is placed at x=5cm. a) Determine the magnitude and direction of the force

on the q1. b) Determine the magnitude and direction of the electric field at the origin.

Answer 1

a)

$$F=(9\cdot10^{9})\frac{(6\cdot10^{-6})(12\cdot10^{-6})}{(0.05-0.03)^2}=1620\ N$$

Positive x-direction.

b)

$$E=-(9\cdot10^{9})\frac{(6\cdot10^{-6})}{(0.05-0.03)^2}+(9\cdot10^{9})\frac{(12\cdot10^{-6})}{(0.05-0.03)^2}\\=1.35\cdot10^8\frac{N}{C}$$

Positive x-direction.