Question

Two particles with equal charge magnitudes 2X10^-7 C but opposite signs are held 15cm apart. Calculate the magnitude and direction of the electric fields at the point midway between the charges.

Answer 1

$E_1=\frac{kq_1}{d^2}$

$E_2=-\frac{kq_2}{d^2}$

$E_{net}=E_1+|-E_2|$

$q_1=q_2=q$

$E_{net}=\frac{2kq}{d^2}$

$$E_{net}=\frac{2\times9\times10^9\times2\times10^{-7}}{0.075^2}=64\times10^4N/C$$

Direction +q to -q