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). |
A capacitor of 2 is charged as shown in the figure. When the switch S is turned to position 2, the percentage of its stored energy dissipated is:
1. | 20% | 2. | 75% |
3. | 80% | 4. | 0% |
A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?
1. | The potential difference between the plates decreases K times |
2. | The energy stored in the capacitor decreases K times |
3. | The change in energy stored is \({1 \over 2} CV^{2}(\frac{1}{K}-1)\) |
4. | The charge on the capacitor is not conserved |
\(\mathrm{A}\), \(\mathrm{B}\) and \(\mathrm{C}\) are three points in a uniform electric field. The electric potential is:
1. | maximum at \(\mathrm{A}\) |
2. | maximum at \(\mathrm{B}\) |
3. | maximum at \(\mathrm{C}\) |
4. | same at all the three points \(\mathrm{A},\mathrm{B} ~\text{and}~\mathrm{C}\) |
Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 and , respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is:
1.
2.
3.
4.
A parallel plate condenser has a uniform electric field E(V/m) in the space between the plates. If the distance between the plates is d(m) and area of each plate is , the energy (joule) stored in the condenser is:
1.
2.
3.
4.
A series combination of n1 capacitors, each of value C1, is charged by a source of potential difference 4 V. When another parallel combination of n2 capacitors, each of value C2, is charged by a source of potential difference V, it has the same (total) energy stored in it as the first combination has. The value of C2 in terms of C1 is:
1.
2. 16C1
3. 2C1
4.
100 capacitors each having a capacity of 10 μF are connected in parallel and are charged by a potential difference of 100 kV. The energy stored in the capacitors and the cost of charging them, if electrical energy costs 108 paise per kWh, will be?
1. | 107 joule and 300 paise |
2. | 5 × 106 joule and 300 paise |
3. | 5 × 106 joule and 150 paise |
4. | 107 joule and 150 paise |
The equivalent capacitance between A and B is:
1. | 2 μF | 2. | 3 μF |
3. | 5 μF | 4. | 0.5 μF |
A parallel plate capacitor has capacitance \(C\). If it is equally filled with parallel layers of materials of dielectric constants \(K_1\) and \(K_2\), its capacity becomes \(C_1\). The ratio of \(C_1\) to \(C\) is:
1. | \(K_1 + K_2\) | 2. | \(\frac{K_{1} K_{2}}{K_{1}-K_{2}}\) |
3. | \(\frac{K_{1}+K_{2}}{K_{1} K_{2}}\) | 4. | \(\frac{2 K_{1} K_{2}}{K_{1}+K_{2}}\) |