A point charge $q$ of mass $m$ is placed at the centre of a fixed ring of charge $Q$ and radius $R.$ What minimum velocity (along the axis of ring) should be give to $q$ so that it would reach far away from ring if (i) $q$ is positive, (ii) $q$ is negative

A right isosceles triangle of side a has charges $q, +2 q$ and $-q$ arranged on its vertices, as shown in figure.

What is the electric potential at point $P,$ midway between the line connecting the $+q$ and $-q$ charges, assuming that $V=0$ at infinity?

A right isosceles triangle of side a has charges $q, +2 q$ and $-q$ arranged on its vertices, as shown in figure.

What is the potential energy $U$ of this configuration of three charges? What is the significance of the sign of your answer?

A right isosceles triangle of side a has charges $q, +2 q$ and $-q$ arranged on its vertices, as shown in figure.

A fourth charge with charge $+3 q$ is slowly moved in from infinity to point $P$. How much work must be done in this process? What is the significance of the sign of your answer?

Find potential at point $P$ in the following cases:

Find potential at point $P$ in the following cases:

Find the value of $k$ if potential at $O$ is zero.

Four charges $2 \mathrm{C}, -3 \mathrm{C}, -4 \mathrm{C} \& 5 \mathrm{C}$ respectively are placed at all the corners of a square. Which of the following statements is true for the point of intersection of the diagonals ?