Homework SourseTwo point charges are located on the x axis The First is a c
Two point charges are located on the x axis. The First is a charge +Q at x = -a. The second is an unknown charge located at x = +3a. The net electric field these charges produce at the origin has a
magnitude of 2kQ/a2. What are the two possible values of the unknown charge?
magnitude of 2kQ/a2. What are the two possible values of the unknown charge?
Solution
field due to +Q = kQ/a^2
field due to q = kq/9a^2
Sum = kQ/a^2 - kq/9a^2 =+/- 2kQ/a^2 (as both are on opposite side of origin)
So -kq/9a^2 = +kQ/a^2
So q = -9Q
else - kq/9a^2 = -3kQ/a^2
q = 27Q
