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
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{{Q^2}}}{{m\nu }}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{4{Q^2}}}{{m{\nu ^2}}}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{2{Q^2}}}{{m{\nu ^2}}}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{3{Q^2}}}{{m{\nu ^2}}}$
An $\alpha$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by above two particals will be.
A metallic sphere has a charge of $10\,\mu C$. A unit negative charge is brought from $A$ to $B$ both $100\,cm$ away from the sphere but $A$ being east of it while $B$ being on west. The net work done is........$joule$
A charge of $8\; mC$ is located at the origin. Calculate the work done in $J$ in taking a small charge of $-2 \times 10^{-9} \;C$ from a point $P (0,0,3\; cm )$ to a point $Q (0,4\; cm , 0),$ via a point $R (0,6\; cm , g \;cm )$
A charged particle of charge $Q $ is held fixed and another charged particle of mass $m$ and charge $q$ (of the same sign) is released from a distance $r.$ The impulse of the force exerted by the external agent on the fixed charge by the time distance between $Q$ and $q$ becomes $2r$ is
If $3$ charges are placed at the vertices of equilateral triangle of charge ‘$q$’ each. What is the net potential energy, if the side of equilateral triangle is $l\, cm$