The charge on $500~\text{cc}$ of water due to protons will be: 

A polythene piece rubbed with wool is found to have a negative charge of $3 \times10^{-7}~\text{C}.$ Transfer of mass from wool to polythene is:
1. $0.7\times10^{-18}~\text{kg}$
2. $1.7\times10^{-17}~\text{kg}$
3. $0.7\times10^{-17}~\text{kg}$
4. $1.7\times10^{-18}~\text{kg}$

If $10^9$ electrons move out of a body to another body every second, how much time approximately is required to get a total charge of $1$ C on the other body?
1. $200$ years
2. $100$ years
3. $150$ years
4. $250$ years

A total charge $Q$ is broken in two parts $Q_1$ and $Q_2$ and they are placed at a distance $R$ from each other. The maximum force of repulsion between them will occur, when:

Two charges $+2$ C and $+6$ C are repelling each other with a force of $12$ N. If each charge is given $-2$ C of charge, then the value of the force will be:

Two positive ions, each carrying a charge $q$, are separated by a distance $d$. If $F$ is the force of repulsion between the ions, the number of electrons missing from each ion will be:
($e$ is the charge on an electron)

The acceleration of an electron due to the mutual attraction between the electron and a proton when they are $1.6~\mathring{A}$ apart is:
$\left(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\right)$