The force on a charge situated on the axis of a dipole is $F$. If the charge is shifted to double the distance, the new force will be

Two point charges $+q$ and $-q$ are held fixed at $(-d, 0)$ and $(d, 0)$ respectively of a $x -y$ coordinate system. Then

Two charges $+q$ and $-3q$ are placed on $x-$ axis separated by a distance $d$. ($-3q$ is right of $q$) Where should a third charge $2q$ be placed such that it will not experience any force ?

If potential at centre of uniformaly charged ring is $V_0$ then electric field at its centre will be (assume radius $=R$ )

Three equal charges are placed at the corners of an equilateral triangle. Which of the graphs below correctly depicts the equally-spaced equipotential surfaces in the plane of the triangle? (All graphs have the same scale.)

Two identical small spheres carry charge of $Q_1$ and $Q_2$ with $Q_1>>Q_2.$ The charges are $d$ distance apart. The force they exert on one another is $F_1.$ The spheres are made to touch one another and then separated to distance $d$ apart. The force they exert on one another now is $F_2.$ Then $F_1/F_2$ is