The force between two point charges $A$ and $B$ is $F$. If $75\%$ of the charge on $A$ is transferred to $B$,then the new force between $A$ and $B$ is:

If $\varepsilon_0$ and $\varepsilon$ represent the permittivity of free space and absolute permittivity of a medium,then the relative permittivity of the medium is:

$A$ force $F$ acts between sodium and chlorine ions of salt (sodium chloride) when placed $1 \ cm$ apart in air. The permittivity of air is $\varepsilon_0$ and the dielectric constant of water is $K$. When a piece of salt is placed in water,the electrical force acting between sodium and chlorine ions $1 \ cm$ apart is:

When $4 \ C$,$Q \ C$,and $1 \ C$ electrical charges are placed along a straight line of length $l$ at positions $0$,$\frac{l}{2}$,and $l$ respectively,what are the values of $Q$ such that the net force on the $4 \ C$ charge is zero,and separately,the net force on the $1 \ C$ charge is zero? (in coulomb)

Two charges $2 C$ and $6 C$ are separated by a finite distance. If a charge of $-4 C$ is added to each of them, the initial force of $12 \times 10^3 \,N$ will change to

$A$ certain charge $2Q$ is divided at first into two parts $q_{1}$ and $q_{2}$. Later,the charges are placed at a certain distance. If the force of interaction between the two charges is maximum,then find the value of $\frac{Q}{q_{1}}$.