The insulation property of air breaks down at V/m. The maximum charge that can be given to a sphere of diameter 5 m is approximately:
1.
2.
3.
4.
The dielectric constant of pure water is 81. Its permittivity will be: (in MKS units)
1.
2.
3.
4.
In a circuit, 5 C of charge is passed through a battery in a given time. The plates of the battery are maintained at a potential difference of 12 V. The work done by the battery is:
1. | 120 J | 2. | 60 J |
3. | 30 J | 4. | 15 J |
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 |
A circuit has section AB as shown in figure. The emf of the cell is 10 V. The potential difference VAB= 5 V. The charge on the capacitor C1 is:
1. | 10 μC | 2. | 5 μC |
3. | 15 μC | 4. | Can't be determine |
A charge \(q_1=5 \times 10^{-8} \mathrm{~C}\) is kept at 3 cm from a charge \(q_2=-2 \times 10^{-8} \mathrm{~C}\). The potential energy of the system relative to the potential energy at infinite separation is:
1. 3 x J
2. –3 x J
3. 9 x J
4. –9 x J
Which of the following statements is correct regarding electrostatics of conductors?
1. | The interior of the conductor with no cavity can have no excess charge in the static situation. |
2. | Electrostatic potential is constant throughout the volume of the conductor. |
3. | Electrostatic potential has the same value inside as that on its surface. |
4. | All of these. |
A positive charge q and a negative charge -q are placed at x= -a and x= +a respectively. The variation of V along x-axis is represented by the graph:
1. | 2. | ||
3. | 4. |
How many capacitors each of and 250 V are required to form a composite capacitor of and 1 kV?
1. | 16 | 2. | 8 |
3. | 64 | 4. | 32 |