Question

1. What are the strength and direction of the electric field at the position indicated by the dot in the following figure? -5.0 nC 2.0 cm 10 nc 4.0 cm 5.0 nC +

Answer 1

We can use the superposition principle.

Q1 = 5 nC

Q2 = -5 nC

Q3 = 10 nC

Electric field

kq 2

kQ1 1.25k x 105 N/C E ri

КQз. 3 3 0.625k x 10 y N/C т; E3

kQ2 2 -0.25kx 10 E2 5 -5 = 0.1768kx10 (î ) N/C)

E E1E2 E3 (1.4267k 0.4482kg) x 105 N/C _

k~9e9 Nm2/C2

$\bar{E}= 10^3 \times (128.403k\hat{x} -40.338k\hat{y}) \hspace{.2cm} N/C$

Direction,

arctan(-40.388/128.403)=-17.4604"