Three positive charges are arranged as shown Find the magnit

Three positive charges are arranged as shown. Find the magnitude of the electric field at. the fourth corner of the rectangle. The Couloumb constant is 8.99 times 10^9 N middot m^2/C^2. Answer in units of N/C. What is the direction of this electric field (as an angle between -180 and 180 measured from the positive x-axis, with counterclockwise positive)? Answer in units of degree .

Solution

1)

Eletric field due to the 1nC charge on the bottom left

E1 = k*q/r^2

= 9*10^9*1*10^-9/2.1^2

= 2.04 N/C

Electric field due to the 9nC

E2 = 9*10^9*9*10^-9/0.1^2

= 8100 N/C

Electric field due to 1nC on the bottom right :

E3 = 9*10^9*1*10^-9/(0.1^2 + 2.1^2)

= 2.04 N/C

So, net electric field:

Enet = 8100 N/C (as other forces are comparatively small relative to E2) <----- approximately

2)

direction = 180 deg <--- approximately