Question

If an object of mass $1kg$ contains $4\times {10}^{22}$ atoms. If electron is removed from every atom of the solid, the charge gained by the solid in $1g$ is then

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

Answer 1

The correct option is B $6.4\times {10}^{-2}C$

Here,
number of electrons removed $=$ number of atoms in $1g$
or $n=\frac{4\times {10}^{20}}{{10}^3}=4\times {10}^{17}$
$\therefore$ charge, $q=ne=4\times {10}^{17}\times 1.6\times {10}^{-19}=6.4\times {10}^{-2}C$