Physics

Problem

Three charges

+4q

Q

and

q

are placed in a straight line of length

\ell

at points at distance

0

\ell/2

and

\ell

respectively from one end of line. What should be the value of

Q

in order to make the net force on

q

to be zero? (a)

-q

(b)

-2q

(c)

-q/2

(d)

4q