The figure shows a set of equipotential surfaces. The magnitude and direction of the electric field that exists in the region are:

1. $10\sqrt{2}$ V/m at $45°$ with x-axis

2. $10\sqrt{2}$ V/m at $-45°$ with x-axis

3. $5\sqrt{2}$ V/m at $45°$ with x-axis

4. $5\sqrt{2}$ V/m at $-45°$ with x-axis

Determine the electric field strength vector if the potential of this field depends on x, y coordinates as V=10axy.

1. $10 \mathrm{a} (\mathrm{y}\hat{\mathrm{i}}+\mathrm{x}\hat{\mathrm{j}})$

2. $-10 \mathrm{a} (\mathrm{y}\hat{\mathrm{i}}+\mathrm{x}\hat{\mathrm{j}})$

3. $-\mathrm{a} (\mathrm{y}\hat{\mathrm{i}}+\mathrm{x}\hat{\mathrm{j}})$

4. $-10 \mathrm{a} (\mathrm{x}\hat{\mathrm{i}}+\mathrm{y}\hat{\mathrm{k}})$

If on the x-axis, the electric potential decreases uniformly from 60 V to 20 V between x=-2 m to x=+2 m, then the magnitude of electric field at the origin:

1. must be 10 V/m.

2. may be greater than 10 V/m.

3. is zero.

4. is 5 V/m.

An infinite conducting sheet has a surface charge density $\mathrm{\sigma }$. The distance between the two equipotential surface is r. The potential difference between these two surfaces is:

1. $\frac{\mathrm{\sigma r}}{2{\mathrm{\epsilon }}_0}$

2. $\frac{\mathrm{\sigma r}}{{\mathrm{\epsilon }}_0}$

3. $\frac{\mathrm{\sigma }}{{\mathrm{\epsilon }}_0\mathrm{r}}$

4. $\frac{\mathrm{\sigma }}{2{\mathrm{\epsilon }}_0\mathrm{r}}$

Two small spheres each carrying a charge q are placed at distance r apart. If one of the spheres is taken around the other in a circular path, the work done will be equal to:

1. Force between them $\times$ r

2. $\frac{\mathrm{Force} \mathrm{between} \mathrm{them}}{2\mathrm{\pi r}}$

3. Force between them $\times 2\mathrm{\pi r}$

4. Zero

Work done in moving a charge q coulomb on the surface of a given charged conductor of potential V is:

1. $\frac{\mathrm{V}}{\mathrm{q}}$ joule

2. $\mathrm{Vq}$ joule

3. $\frac{\mathrm{q}}{\mathrm{V}}$ joule

4. Zero

If an $\mathrm{\alpha }$-particle and a proton are accelerated from rest by a potential difference of 1 megavolt, then the ratio of their kinetic energies will be:

1. $\frac{1}{2}$

2. 1

3. 2

4. 4

Three charges -q, Q and -q are placed respectively at equal distances on a straight line. If the potential energy of the system of three charges is zero, then what is the ratio of Q:q?

1. 1: 1

2. 1: 2

3. 1: 3

4. 1: 4

A particle A has charge +q and another particle B has charge +4q with each of them having the same mass m. When allowed to fall from rest through the same electric potential difference, the ratio of their speeds $\frac{{\mathrm{v}}_{\mathrm{A}}}{{\mathrm{v}}_{\mathrm{B}}}$ will become:

1. 1: 2

2. 2: 1

3. 1: 4

4. 4: 1

If \(50~\text{J}\) of work must be done to move an electric charge of \(2~\text{C}\) from a point where the potential is \(-10~\text {volts}\) to another point where the potential is \(\text{V volts}\), then the value of \(\mathrm{V}\) is:
1. \(5~\text {volts}\)
2. \(-15~\text {volts}\)
3. \(+15~\text {volts}\)
4. \(+10~\text {volts}\)