A bullet of mass 2g is having a charge of $2\mathrm{\mu C}$. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of $10<mspace\; width="1em"></mspace>{\mathrm{ms}}^{-1}$ ?

1. 20 kV

2. 5 V

3. 50 kV

4. 5 kV

An electric dipole of moment $\overrightarrow{\mathrm{p}}$ is lying along a uniform electric field $\overrightarrow{\mathrm{E}}$. The work done in rotating the dipole by $90°$ is

1. $\sqrt{2}pE$

2. $\frac{\mathrm{pE}}{2}$

3. 2pE

4. pE

A parallel plate air capacitor is charged to a potential difference of V volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates

1. decreases

2. does not change

3. becomes zero

4. increases.

Charges +q and -q are placed at points  A and B respectively which are distance 2L apart, C is the midpoint between A and B. The work done in moving a charge +Q along the semicircle CRD is

1. $\frac{qQ}{2\pi {\epsilon }_{0}L}$

2. $\frac{qQ}{\mathit{6}\pi {\epsilon }_{0}L}$

3. $-\frac{qQ}{\mathit{6}\pi {\epsilon }_{0}L}$

4. $\frac{qQ}{\mathit{4}\pi {\epsilon }_{0}L}$

Two condensers one of capacity C and other of capacity C/2 are connected to a V-volt battery, as shown. The work done in charging fully both the condensers is

1. $\frac{1}{4}C{V}^2$

2. $\frac{3}{2}C{V}^2$

3. $\frac{1}{2}C{V}^2$

4. $2{\mathrm{CV}}^2$

Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be

1. $3\mathrm{C},<mspace\; width="1em"></mspace>\frac{\mathrm{V}}{3}$

2. $\frac{\mathrm{C}}{3}$, 3V

3. 3C, 3V

4. $\frac{C}{3},<mspace\; width="1em"></mspace>\frac{V}{3}$

A parallel plate condenser has a uniform electric field E ($\mathrm{V}<mspace\; width="1em"></mspace>{\mathrm{m}}^{-1}$) in the space between the plates. If the distance between the plates is d (m) and area of each plate is A $\left({\mathrm{m}}^2\right)$, the energy (joules) stored in the condenser is

1. $\frac{1}{2}{\epsilon }_0{E}^{2}Ad$

2. $E^{2}Ad/{\epsilon }_0$

3. $\frac{1}{2}{\epsilon }_0{E}^2$

4. ${\mathrm{\epsilon }}_0\mathrm{EAd}$

Three charges each +q are placed at the corners of an isosceles triangle ABC of sides BC and AC equal to 2a. D and E are the midpoints of BC and CA. The work done in taking a charge Q from D to E is

1. $\frac{3qQ}{4\pi {\epsilon }_{0}a}$

2. $\frac{3qQ}{8\pi {\epsilon }_{0}a}$

3. $\frac{qQ}{4\pi {\epsilon }_{0}a}$

4. zero

A, B and C are three points in a uniform electric field. The electric potential is

1. maximum at A

2. maximum at B

3. maximum at C

4. same at all the three points A, B and C

A conducting sphere of radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere respectively are

1. zero and $\frac{Q}{4\pi {\epsilon }_0{R}^2}$

2. $\frac{Q}{4\pi {\epsilon }_{0}R}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>zero$

3. $\frac{Q}{4\pi {\epsilon }_{0}R}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>\frac{Q}{4\pi {\epsilon }_0{R}^2}$

4. Both are zero