When \(10^{19}\) electrons are removed from a neutral metal plate, the electric charge on it is? 

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)
1. \(\frac{4 \pi \varepsilon_{0} F d^{2}}{e^{2}}\)
2. \(\sqrt{\frac{4 \pi \varepsilon_{0} F d^{2}}{d^{2}}}\)
3. \(\sqrt{\frac{4 \pi \varepsilon_{0} F d^{2}}{e^{2}}}\)
4. \(\frac{4 \pi \varepsilon_{0} F d^{2}}{q^{2}}\)

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

Two point charges \(A\) and \(B\), having charges \(+Q\) and \(-Q\) respectively, are placed at a certain distance apart and the force acting between them is \(F.\) If \(25\%\) charge of \(A\) is transferred to \(B\), then the force between the charges becomes: