Question

Two point charges 2uC and 8uC are placed 12 cm apart. Find the position of the point where electric field resultant will be zero

Answer 1

2/x^2 = 8/(12-x)^2

1/x^2 = 4 /(12-x)^2

4 x^2 = 144 - 24 x + x^2

3 x^2 + 24 x - 144 = 0

x^2 + 8 x - 48 = 0

(x+12)(x-4) = 0

x = 4 cm
then 12 - x = 8 cm


check
2/16 = 8/64 ??? yes right

Answer 2

r is the point where they cancel

E1 = kq1/r^2
E2 = kq2/(.12-r)^2
Drop the k's set them equal and solve for r. You'll have to cross multiply and solve the quadratic.

Answer 3

Nothing

Answer 4

Nothing

Answer 5

Thanks