The figure shows some of the equipotential surfaces. Magnitude and direction of the electric field is given by

1. 200 V/m, making an angle ${120}^{\circ }$with the x-axis

2. 100 V/m, pointing towards negative x-axis

3. 200 V/m, making an angle $-{60}^{\circ }$with the x-axis

4. 100 V/m, making an angle ${30}^{\circ }$ with the x-axis

Electric field in a region is increasing in magnitude along x-direction. The equipotential surfaces associated are :

1. Planes parallel to xy-plane

2. Planes parallel to yz-plane 

3. Co-axial cylinders around the x-axis

4. All of these

If a unit positive charge is taken from one point to another on an equipotential surface, then

1. Work is done on the charge

2. Work is done by the charge

3. Potential energy of the charged is changed

4. No work is done on the charge

When a test charge is brought in from infinity along the perpendicular bisector of an electric dipole, the work done is:

1. Positive

2. Zero

3. Negative

4. None of these

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. $\frac{\mathrm{Force}<mspace\; width="1em"></mspace>\mathrm{between}<mspace\; width="1em"></mspace>\mathrm{them}}{2\mathrm{\pi r}}$

3. Force between them $\times <mspace\; width="1em"></mspace>2\mathrm{\pi r}$

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

In the electric field of a point charge q, a certain charge is carried from point A to B, C, D, and E, the work done:

1. is least along the path AB

2. is least along the path AD

3. is zero along any one of the paths AB, AC and AE

4. is least along AE.

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

1. Force between them × r

2. Force between them × 2πr

3. Force between them / 2πr

4. Zero

If a unit positive charge is taken from one point to another over an equipotential surface, then -

1. Work is done on the charge

2. Work is done by the charge

3. Work done is constant

4. No work is done