1. Electric Charges and Fields
hard

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)

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

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

(AIPMT-2010)

Solution

According to Coulomb's law, the force of repulsion between the two positive ions each of charge $q$ separated by a distance $d$ is given by

$F =\frac{1}{4 \pi \varepsilon_{0}} \frac{(q)(q)}{d^{2}} $

$F =\frac{q^{2}}{4 \pi \varepsilon_{0} d^{2}}$

$q^{2} =4 \pi \varepsilon_{0} F d^{2} $

$q =\sqrt{4 \pi \varepsilon_{0} F d^{2}}……….(i)$

Since, $q=ne$

where,

$n=$ number of electrons missing from each ion

$e=$ magnitude of charge on electron

$\therefore n = \frac{q}{e}$

$n = \frac{{\sqrt {4\pi {\varepsilon _0}F{d^2}} }}{e}$      (Using $(i)$)

$=\sqrt{\frac{4 \pi \varepsilon_{0} F d^{2}}{e^{2}}}$

Standard 12
Physics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.