two charges 4q nd -q r placed a distance r apart. a charge Q is placed exactly mid-way between them. what will be the value of Q so that the charge 4q expiriences no net force?

q/4

f=k4Qq/r2/4

therefore f=k16Qq/r2

if q=q/16 then the f=kqq/r2

on other side of the line

f=k-q*q/r2

therefore both answers cancel each other

so there is no net force

hence value of q should be   q/16...