Two charges 4q and q are placed at a distance I another charge Q is placed at the midpoint of line joining the charges 4q and q If net force on charge q is zero, then value of Q is:

Question

Two charges 4q and q are placed at a distance I another charge Q is placed at the midpoint of line joining the charges 4q and q If net force on charge q is zero, then value of Q is: (A)  +q  (B)  -q  (C)  +2q  (D)  3q

Tardigrade Admin · Accepted Answer

On charge Q, both 4q and q charge apply force. Net force of Q should be zero. K(4q. q/l2)+(K Q.q/(1/2)2)=0 Q=-q

Q. Two charges $4 q$ and $q$ are placed at a distance $I$ another charge Q is placed at the midpoint of line joining the charges $4 q$ and $q$ If net force on charge $q$ is zero, then value of $Q$ is:

$+ q$

$- q$

$+ 2 q$

$3 q$

On charge Q, both 4q and q charge apply force.
Net force of Q should be zero. $K \frac{4 q . q}{l ^{2}} + \frac{K Q . q}{( 1/2 ) ^{2}} = 0$ $Q = - q$

Q. Two charges 4q and q are placed at a distance I another charge Q is placed at the midpoint of line joining the charges 4q and q If net force on charge q is zero, then value of Q is:

+q

−q

+2q

3q