Question

three charge 4q,Q and q are placed in straight line l at of length lat points 0, l\2,l . what should bevalye of Q in order tomake the net force onq to be 0

Answer 1

Hi...

Two force are acting on q ,one due to 4q and second due to Q..

F1 = 1/4∏ε (4q)q/l2

F2 = 1/4∏ε (Q)q/(l/2)2

= 1/4∏ε (4Q)q/l2

F1 +F2 =0

1/4∏ε (4q)q/l2 + 1/4∏ε (4Q)q/l2 =0

Q=-q


Hope this helps u!!

Answer 2

Answer: -q

Explanation:

F1 = k(4q)(q)/l^2

F2 = k(Q)(q)/(l/2)^2

For net force to be zero

F1 + F2 = 0

Therefore q = -q