Question

Two charges are on the x-axis. Charge q 1= +35 nC is at x = 3.00 cm while charge q 2= -65nC is at x = 6.00 cm. Find the magnitude and direction of

a) the electric force that q 1 exerts on q2 ; and

b) the electric force the q 2 exerts on q1 .

2. A positive charge of 10 -8 coulombs (C) experiences a force of 0.95 N when located at a certain point in an electric field. Find the intensity (magnitude) of the electric field at that point.

Answer 1

(1)Force

$$F_{12}=\frac{kq_1q_2}{r^2}=-\frac{9\times10^9\times35\times10^{-9}\times65\times10^{-9}}{0.03^2}=-0.02275N$$

(2)Force

$$F_{21}=\frac{kq_1q_2}{r^2}=-\frac{9\times10^9\times35\times10^{-9}\times65\times10^{-9}}{0.03^2}=-0.02275N$$

2

Electric field

$E=\frac{F}{q}$

$E=\frac{0.95}{10^{-8}}=95\times10^6N/c$

Magnitude of electric field

$|E|=95\times10^6N/c$