On rotating a point charge having a charge \(q\) around a charge \(Q\) in a circle of radius \(r\), the work done will be:
1. | \(q \times2 \pi r\) | 2. | \(q \times2 \pi Q \over r\) |
3. | zero | 4. | \(Q \over 2\varepsilon_0r\) |
The work done to move a charge along an equipotential from A to B:
1. | can not be defined as \(-\int_{\mathrm{A}}^{\mathrm{B}} \text { E. dl. }\) |
2. | must be defined as \(-\int_{\mathrm{A}}^{\mathrm{B}} \text { E. dl. }\) |
3. | is zero |
4. | can have a non-zero value. |
The diagrams below show regions of equipotentials.
A positive charge is moved from A to B in each diagram. Then:
1. | the maximum work is required to move q in figure(iii). |
2. | in all four cases, the work done is the same. |
3. | the minimum work is required to move q in the figure(i). |
4. | the maximum work is required to move q in figure(ii). |
1. | zero | 2. | \(180^{\circ}\) |
3. | \(90^{\circ}\) | 4. | \(45^{\circ}\) |
A cube of a metal is given a positive charge Q. For the above system, which of the following statements is true?
1. | Electric potential at the surface of the cube is zero. |
2. | Electric potential within the cube is zero. |
3. | Electric field is normal to the surface of the cube. |
4. | Electric field varies within the cube. |
Consider a uniform electric field in the Z-direction. The potential is constant:
a. | in all space |
b. | for any x for a given z |
c. | for any y for a given z |
d. | on the x-y plane for a given z |
1. (a, b, c)
2. (a, c, d)
3. (b, c, d)
4. (c, d)
Some equipotential surfaces are shown in figure. The electric field at points A, B and C are respectively:
1. | \(1 \mathrm{~V} / \mathrm{cm}, \frac{1}{2} \mathrm{~V} / \mathrm{cm}, 2 \mathrm{~V} / \mathrm{cm} \text { (all along +ve X-axis) }\) |
2. | \(1 \mathrm{~V} / \mathrm{cm}, \frac{1}{2} \mathrm{~V} / \mathrm{cm}, 2 \mathrm{~V} / \mathrm{cm} \text { (all along -ve X-axis) }\) |
3. | \(\frac{1}{2} \mathrm{~V} / \mathrm{cm}, 1 \mathrm{~V} / \mathrm{cm}, 2 \mathrm{~V} / \mathrm{cm} \text { (all along +ve X-axis) }\) |
4. | \(\frac{1}{2} \mathrm{~V} / \mathrm{cm}, 1 \mathrm{~V} / \mathrm{cm}, 2 \mathrm{~V} / \mathrm{cm} \text { (all along -ve X-axis) }\) |
The electric potential in a certain region of space is given by V = –8x2 + 4x, where V is in volt and x is in metre. In this region, the equipotential surface is:
1. | plane parallel to yz plane |
2. | plane parallel to the x-axis |
3. | concentric circle centered at the origin |
4. | coaxial cylinder with axis parallel to the y-axis |
Equipotential surfaces:
a. | are closer in regions of large electric fields compared to regions of lower electric fields. |
b. | will be more crowded near the sharp edges of a conductor. |
c. | will be more crowded near regions of large charge densities. |
d. | will always be equally spaced. |
Choose the correct statement(s):
1. a, b and c
2. a, c and d
3. b, c and d
4. c and d
Equipotential at a great distance from a collection of charges whose total sum is not zero are approximately:
1. | spheres | 2. | planes |
3. | paraboloids | 4. | ellipsoids |