Question

Two identical spheres carrying charges - ${9 \, \mu C}$ and ${ 5 \, \mu C}$ respectively are kept in contact and then separated from each other. Point out true statement from the following. In each sphere

• A. $1.25 \times 10^{13}$ electrons are in deficit
• B. $1.25 \times 10^{13}$ electrons are in excess
• C. $2.15 \times 10^{13}$ electrons are in excess
• D. $2.15 \times 10^{13}$ electrons are in deficit

Answer 1

Answer: (B)

$1.25 \times 10^{13}$ electrons are in excess

Answer 2

After initial contact and separation, each sphere will be having -${2\, \mu C}$ each
$\therefore \:\:\:\: n = \frac{ -2 \times 10^{-6} }{ -1.6 \times 10^{-19}} = 1.25 \times 10^{13}$
$i.e. \:\: 1.25 \times 10^{13}$ electrons as in excess in each sphere.