A hollow sphere of radius \(1~\text{m}\) is given a positive charge of \(10~\mu\text{C}\). The electric field at the centre of the hollow sphere will be:
1. \(60\times10^{3}~\text{Vm}^{-1}\)
2. \(90\times10^{3}~\text{Vm}^{-1}\)
3. zero
4. infinite

A charge \(q\) is placed in a uniform electric field \(E.\) If it is released, then the kinetic energy of the charge after travelling distance \(y\) will be:
1. \(qEy\)
2. \(2qEy\)
3. $\frac{qEy}{2}$
4. $\sqrt{qEy}$

The electric field at the equator of a dipole is \(E.\) If the strength of the dipole and distance are now doubled, then the electric field will be:

A point \(Q\) lies on the perpendicular bisector of an electric dipole of dipole moment \(p.\) If the distance of \(Q\) from the dipole is \(r\) (much larger than the size of the dipole), then the electric field at \(Q\) is proportional to:
1. \(p^{2}\) and \(r^{-3}\)
2. \(p\) and \(r^{-2}\)
3. \(p^{-1}\) and \(r^{-2}\)
4. \(p\) and \(r^{-3}\)

In Millikan oil drop experiment, a charged drop falls with a terminal velocity v. If an electric field E is applied vertically upwards it moves with terminal velocity 2v in upward direction. If electric field reduces to E/2 then its terminal velocity will be:
1. v/2
2. v
3. 3v/2
4. 2v

The electric field at centre \(O\) of a semicircle of radius \(a\) having linear charge density \(\lambda\) is given by:

     
1. \(\frac{2\lambda}{\epsilon_0 a}\)
2. \(\frac{\lambda\pi}{\epsilon_0 a}\)
3. \(\frac{\lambda}{2\pi \epsilon_0 a}\)
4. \(\frac{\lambda}{\pi \epsilon_0 a}\)
 

If a charge \(Q\) is situated at the corner of a cube, the electric flux passing through all six faces of the cube is:
1. \(\frac{Q}{6\varepsilon_0}\)
2. \(\frac{Q}{8\varepsilon_0}\)
3. \(\frac{Q}{\varepsilon_0}\)
4. \(\frac{Q}{2\varepsilon_0}\)

Who evaluated the mass of electron indirectly with help of charge:
1. Thomson
2. Millikan
3. Rutherford
4. Newton

If a charge Q µC is placed at the centre of the cube, the flux (In SI unit) coming out from any surface will be: 

1.  $\frac{Q}{6{\epsilon }_0}$ $\times$ ${10}^{-6}$

2.  $\frac{Q}{6{\epsilon }_0}$ $\times$ ${10}^{-3}$

3.  $\frac{Q}{2{\epsilon }_0}$ $$

4. $\frac{Q}{8{\epsilon }_0}$ $$

A dipole of moment $\overrightarrow{p}$ is placed in uniform electric field $\overrightarrow{E}$. The torque acting on it is given by:
1. \(\vec{\tau }=\vec{p}.\vec{E}\)
2. \(\vec{\tau }=\vec{p} \times\vec{E}\)
3. \(\vec{\tau }=\vec{p}+\vec{E}\)
4. \(\vec{\tau }=\vec{p}-\vec{E}\)