It doesn’t seem like you gave enough info to answer the question but I can give you some options based on what it could look like.
+ charges —> E points outward/away
— charges —> E points toward/in
If the charges are the same sign (both + or both -):
- Calculate each of their electric fields at the middle, then subtract them. The field will point in the direction of whichever E was larger. If they are the same sign and same magnitude, the electric field will be 0.
Ex.
+ 1C Middle point +3C
Pretend the distance from each point to the middle is 2m.
Field from the +1C points out, pushes the middle point to the right
Field from the +3C points out, pushes the middle point to the left
E = kQ/ r^2
For the +1 charge:
E = (9*10^9)(1)/(2^2) = 2.25 * 10^9 N/C
For the +3 charge:
E = (9*10^9)(3)/(2^2) = 6.75 * 10^9 N/C
E at the center = 6.75*10^9 - 2.25 * 10^9 = 5.00*10^9 N/C and it would point where the +3 field pointed = to the left
If the charges are opposite signs (one + and one -)
- Calculate each of their electric fields at the middle and then add them together. The field will point in the direction that they both point.
Ex.
+ 1C Middle point -3C
Pretend the distance from each point to the middle is 2m.
Field from the +1C points out, pushes the middle point to the right
Field from the -3C points in, pulling the middle line to the right
E = kQ/ r^2
For the +1 charge:
E = (9*10^9)(1)/(2^2) = 2.25 * 10^9 N/C
For the -3 charge:
E = (9*10^9)(3)/(2^2) = 6.75 * 10^9 N/C (absolute value - don’t worry about the negative sign)
E at the center = 6.75*10^9 + 2.25 * 10^9 = 9.00*10^9 N/C and it would point where both fields pointed = to the right
Hopefully this helps you answer your question. If not please give more info so we can better understand the question. :)
