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

The charge on 500 cc of water due to protons will be: 

A polythene piece rubbed with wool is found to have a negative charge of $3\times {10}^{-7} C$. Transfer of mass from wool to polythene is:
1. 0.7 × 10 ^{- 18}   kg
2. 1.7 × 10 ^{- 17}   kg
3. 0.7 × 10 ^{- 17}   kg
4. 1.7 × 10 ^{- 18}   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 charges 2 $\mathrm{\mu C}$ and 8 $\mathrm{\mu C}$ are separated by 6 cm. The neutral point is at:

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. $\frac{4\pi {\epsilon }_{0}F{d}^2}{e^2}$

2. $\sqrt{\frac{4\pi {\epsilon }_{0}F{d}^2}{d^2}}$

3. $\sqrt{\frac{4\pi {\epsilon }_{0}F{d}^2}{e^2}}$

4. $\frac{4\pi {\epsilon }_{0}F{d}^2}{q^2}$

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

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:
1. $\frac{4F}{3}$

2. $F$

3. $\frac{9F}{16}$

4. $\frac{16F}{9}$