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

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:
\(\left(\dfrac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\right)\)

Two small spheres each having the charge \(+Q\) are suspended by insulating threads of length \(L\) from a hook. If this arrangement is taken in space where there is no gravitational effect, then the angle between the two suspensions and the tension in each will be:

1. ${180}^o,$ $\frac{1}{4\pi {\epsilon }_0}\frac{Q^2}{{\left(2L\right)}^2}$

2. ${90}^o,$ $\frac{1}{4\pi {\epsilon }_0}\frac{Q^2}{L^2}$

3. ${180}^o,$ $\frac{1}{4\pi {\epsilon }_0}\frac{Q^2}{2L^2}$

4. ${180}^o,$ $\frac{1}{4\pi {\epsilon }_0}\frac{Q^2}{L^2}$ 

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:

Suppose the charge of a proton and an electron differ slightly. One of them is \(-e\), the other is (\(e+\Delta e\)). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance \(d\) (much greater than atomic size) apart is zero, then$$ \(\Delta e\) is of the order of? (Given mass of hydrogen ${\mathrm{}}_{}$\(m_h = 1.67\times 10^{-27}~\text{kg}\)$$)
1. \(10^{-23}~\text{C}\)
2. \(10^{-37}~\text{C}\)
3. \(10^{-47}~\text{C}\)
4. \(10^{-20}~\text{C}\)

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)

An electron is moving around the nucleus of a hydrogen atom in a circular orbit of radius \(r\). The Coulomb force $\overrightarrow{F}$ on the electron is: (Where $K=\frac{1}{4\pi {\epsilon }_0}$) 
1. $-K\frac{e^2}{r^3}\hat{r}$
2. $K\frac{e^2}{r^3}\overrightarrow{r}$
3. $-K\frac{e^2}{r^3}\overrightarrow{r}$
4. $K\frac{e^2}{r^2}\hat{r}$