Question

In a process, when two bodies are charged by rubbing against each other, one becomes positively charged while the other becomes negatively charged. Then

• A. Mass of each body remains unchanged
• B. Mass of positively charged body slightly increases
• C. Mass of negatively charged body slightly decreases
• D. Mass of each body changes slightly but the total mass of system remains the same

Answer 1

The correct option is D Mass of each body changes slightly but the total mass of system remains the same

The transfer of electrons from one body to the other produces charge on the body.

Hence,
$\text{number of electrons given by one body}$$=\text{number of electrons obtained by the other body}$

So, the mass of the negatively charged body slightly increases while the mass of the positively charged body slightly decreases. However, the total mass of the system remains the same.

$\begin{array}{c}\text{Why this question ?}\\ \text{Tip: Conservation of mass is applicable until some part of mass}\\ \text{is converted into energy, which happens in nuclear reactions.}\end{array}$