Question

There are $4\times {10}^{23}$ atoms in a metal sphere. If one electron is removed from $0.1\%$ of atoms, what will be the charge on the sphere?

• A. $-6.4C$
• B. $64C$
• C. $0.64C$
• D. $-64C$

Answer 1

The correct option is D $-64C$

Given,

$n=4\times {10}^{23}\times 0.1$%

$n=4\times {10}^{23}\times \frac{0.1}{100}=4\times {10}^{20}$

$e=1.6\times {10}^{-19}C$

The charge is quantised, $q=ne$

$q=4\times {10}^{20}\times 1.6\times {10}^{-19}=64C$

The electron is negative charge particle.

So,$q=-64C$

The correct option is D.