Two positive ions, each carrying a charge $q,$ are separated by a distance $d.$ If $F$ is the force of repulsion between the ions, the number of electrons missing from each ion will be  ($e$ being the charge on an electron)

  • [AIPMT 2010]
  • A

    $\frac{{4\pi {\varepsilon _0}F{d^2}}}{{{e^2}}}$

  • B

    $\sqrt {\;\frac{{4\pi {\varepsilon _0}F{e^2}}}{{{d^2}}}} $

  • C

    $\sqrt {\;\frac{{4\pi {\varepsilon _0}F{d^2}}}{{{e^2}}}} $

  • D

    $\;\frac{{4\pi {\varepsilon _0}F{d^2}}}{{{q^2}}}$

Similar Questions

Two identical tennis balls each having mass $m$ and charge $q$ are suspended from a fixed point by threads of length $l$. What is the equilibrium separation when each thread makes a small angle $\theta$ with the vertical?

  • [JEE MAIN 2021]

A charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium, if $q$ is equal to

  • [AIEEE 2002]

A paisa coin is made up of $\mathrm{Al - Mg}$ alloy and weighs $0.75\, g$ It is electrically neutral and contains equal amounts of positive and negative charge of magnitude $34.8$ $\mathrm{kC}$. Suppose that these equal charges were concentrated in two point charges separated by :

$(i)$ $1$ $\mathrm{cm}$ $(\sim \frac{1}{2} \times $ diagonal of the one paisa coin $)$

$(ii)$ $100\,\mathrm{m}$ $(\sim $ length of a long building $)$

$(iii)$ $10^6$ $\mathrm{m}$ (radius of the earth).

Find the force on each such point charge in each of the three cases. What do you conclude from these results ?

The electrostatic force on a small sphere of charge $0.4 \;\mu\, C$ due to another small sphere of charge $-0.8 \;\mu \,C$ in air is $0.2\; N .$

$(a)$ What is the distance between the two spheres?

$(b)$ What is the force on the second sphere due to the first?

Four point $+ve$ charges of same magnitude $(Q)$ are placed at four corners of a rigid square frame as shown in figure. The plane of the frame is perpendicular to $Z$ axis. If a $-ve$ point charge is placed at a distance $z$ away from the above frame $(z<< L)$ then

  • [AIIMS 2005]