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
The electric potential difference between two parallel plates is \(2000 ~\mathrm V\). If the plates are separated by \(2~ \mathrm {mm}\), what is the magnitude of the electrostatic force on a charge of \(4 \times 10^{-6}~ \mathrm C\)located midway between the plates?
1. | \(4~\mathrm N\) | 2. | \(6~\mathrm N\) |
3. | \(8~\mathrm N\) | 4. | \(1.5 \times 10^{-6}~ \mathrm N\) |
Two condensers of capacity 0.3 and 0.6 are connected in series. The combination is connected across a potential of 6 V. The ratio of energies stored by the condensers will be:
1.
2. 2
3.
4. 4
A parallel plate air capacitor is charged to potential difference V. After disconnecting the 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. increases.
3. becomes zero.
4. does not change.
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 |
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 |
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. | \(\frac{1}{2} \mathrm{~V} / \mathrm{cm}, 1 \mathrm{~V} / \mathrm{cm}, 2 \mathrm{~V} / \mathrm{cm} \text { (all along -ve X-axis) }\) |
In a certain region of space with volume \(0.2\) m3, the electric potential is found to be \(5\) V throughout. The magnitude of electric field in this region is:
1. \(0.5\) N/C
2. \(1\) N/C
3. \(5\) N/C
4. zero
A short electric dipole has a dipole moment of \(16 \times 10^{-9} ~\text{C-}\text{m}\). The electric potential due to the dipole at a point at a distance of \(0.6~\text{m}\) from the centre of the dipole situated on a line making an angle of \(60^{\circ}\) with the dipole axis is: \(\left( \frac{1}{4\pi \varepsilon_0}= 9\times 10^{9}~\text{N-m}^2/\text{C}^2\right)\)
1. \(200~\text{V}\)
2. \(400~\text{V}\)
3. zero
4. \(50~\text{V}\)
The capacitance of a parallel plate capacitor with air as a medium is \(6~\mu\text{F}\). With the introduction of a dielectric medium, the capacitance becomes \(30~\mu\text{F}\). The permittivity of the medium is:\(\left(\varepsilon_0=8.85 \times 10^{-12} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\right )\)
1. | \(1.77 \times 10^{-12}~ \text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |
2. | \(0.44 \times 10^{-10} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |
3. | \(5.00 ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |
4. | \(0.44 \times 10^{-13} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |