Question

Four point charges are located at the corners of a square. Each charge has magnitude 4.50 nC and the square has sides of length 2.80 cm. Find the magnitude of the electric field (in N/C) at the center of the square if all of the charges are positive and three of the charges are positive and one is negative.

Answer 1

Answer:

Explanation:

$r^2 = [\frac{l}{2}]^2 +[\frac{l}{2}]^2$

$r^2 = \frac{2l^2}{4}$

$r^2 = \frac{l^2}{2}$

we know that electric field is given as

$E = \frac{kq}{r^2}$

from the figure electric field c and electric field a CANCEL OUT EACH OTHER

so, we have E_B and E_D is toward -q direction

$E_{net} = 2E = 2* \frac{kq}{r^2} = \frac{2kq}{r^2}$

$E_{net} =\frac{2kq}{(\frac{l}{2})^2}$

$E_{net} =\frac{4kq}{l^2}$

$E_{net} = \frac{4*9*10^{9} *3.2*10^{-9}}{(2*10^{-2})^2}$

$E_{net} = 28.8 *10^{-4} N/C$