In free space, a particle $A$ of charge $1\,\mu C$ is held fixed at a point $P.$ Another particle $B$ of the same charge and mass $4\,\mu g$ is kept at a distance of $1\,mm$ from $P$. If $B$ is released, then its velocity at a distance of $9\,mm$ from $P$ is [ Take $\frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}\,N{m^2}{C^{ – 2}}$ ]

In an electrical circuit, a battery is connected to pass $20\, C$ of charge through it in a certain given time. The potential difference between two plates of the battery is maintained at $15\, V$. The work done by the battery is ……….. $J$.

A particle of mass $100\, gm$ and charge $2\, \mu C$ is released from a distance of $50\, cm$  from a fixed charge of $5\, \mu C$. Find the speed of the particle when its distance  from the  fixed charge becomes $3\, m$. Neglect any other force……..$m/s$

A particle of mass $m$ and charge $q$ is placed at rest in a uniform electric field $E$ and then released. The kinetic energy attained by the particle after moving a distance $y$ is

Two identical particles of mass m carry a charge $Q$ each. Initially one is at rest on a smooth horizontal plane and the other is projected along the plane directly towards first particle from a large distance with speed $v.$ The closest distance of approach be