Question

If an object of mass $1\,kg$ contains $4\times 10^{20}$ atoms. If one electron is removed from every atom of the solid, the charge gained by the solid in $1\,g$ is

• A. $2.8\,C$
• B. $6.4 \times 10^{-2}\, C$
• C. $3.6 \times 10^{-3}\, C$
• D. $9.2 \times 10^{-4}\, C$

Answer 1

Answer: (B)

Here,
number of electrons removed = number of atoms in $1\,g$
or $n=\frac{4\times10^{20}}{10^{3}}=4\times10^{17}$
$\therefore $ charge, $q=n e = 4\times10^{17}\times1.6\times10^{-19}\,C=6.4\times10^{-2}\,C$