When $4 \mathrm{C}, \mathrm{Q} C$ and $1 \mathrm{C}$ electrical charges are placed along a straight line of…
When $4 \mathrm{C}, \mathrm{Q} C$ and $1 \mathrm{C}$ electrical charges are placed along a straight line of length ' $l$ ' at 0 , $\frac{l}{2}$ and $l$ respectively. The respective values of $\mathrm{Q}$ so that the net force on $4 \mathrm{C}$ is zero and
$1 \mathrm{C}$ is zero separately are (in coulomb)