Q. No.The plates of a parallel plate capacitor have an area of \(90~\text{cm}^2\) each and are separated by \(2.5~\text{mm}.\) The capacitor is charged by connecting it to a \(400~\text{V}\) supply. How much electrostatic energy is stored by the capacitor?
1. \(1.7\times10^{-6}~\text J\)
2. \(2.12\times10^{-6}~\text J\)
3. \(2.55\times10^{-6}~\text J\)
4. \(1.66\times10^{-6}~\text J\)
1. \(1.7\times10^{-6}~\text J\)
2. \(2.12\times10^{-6}~\text J\)
3. \(2.55\times10^{-6}~\text J\)
4. \(1.66\times10^{-6}~\text J\)
In a certain region of space with volume \(0.2~\text m^3,\) the electric potential is found to be \(5~\text V\) throughout. The magnitude of the electric field in this region is:
1. \(0.5~\text {N/C}\)
2. \(1~\text {N/C}\)
3. \(5~\text {N/C}\)
4. zero
| 1. | can not be defined as \(-\int_{A}^{B} { \vec E\cdot \vec{dl}}\) |
| 2. | must be defined as \(-\int_{A}^{B} {\vec E\cdot \vec{dl}}\) |
| 3. | is zero |
| 4. | can have a non-zero value. |
| a. | in all space |
| b. | for any \(x\) for a given \(z\) |
| c. | for any \(y\) for a given \(z\) |
| d. | on the \(x\text-y\) plane for a given \(z\) |
| 1. | (a), (b), (c) | 2. | (a), (c), (d) |
| 3. | (b), (c), (d) | 4. | (c), (d) |
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. |
Some equipotential surfaces are shown in the figure. The electric field at points \(A\), \(B\) and \(C\) are respectively:
| 1. | \(1~\text{V/cm}, \frac{1}{2} ~\text{V/cm}, 2~\text{V/cm} \text { (all along +ve X-axis) }\) |
| 2. | \(1~\text{V/cm}, \frac{1}{2} ~\text{V/cm}, 2 ~\text{V/cm} \text { (all along -ve X-axis) }\) |
| 3. | \(\frac{1}{2} ~\text{V/cm}, 1~\text{V/cm}, 2 ~\text{V/cm} \text { (all along +ve X-axis) }\) |
| 4. | \(\frac{1}{2}~\text{V/cm}, 1~\text{V/cm}, 2 ~\text{V/cm} \text { (all along -ve X-axis) }\) |
Three charges, each \(+q\), are placed at the corners of an equilateral triangle \(ABC\) of sides \(BC\), \(AC\), and \(AB\). \(D\) and \(E\) are the mid-points of \(BC\) and \(CA\). The work done in taking a charge \(Q\) from \(D\) to \(E\) is:
| 1. | \(\frac{3qQ}{4\pi \varepsilon_0 a}\) | 2. | \(\frac{3qQ}{8\pi \varepsilon_0 a}\) |
| 3. | \(\frac{qQ}{4\pi \varepsilon_0 a}\) | 4. | \(\text{zero}\) |
| 1. | \(8~\text{V/m},\) along the negative \(x\text-\)axis |
| 2. | \(8~\text{V/m},\) along the positive \(x\text-\)axis |
| 3. | \(16~\text{V/m},\) along the negative \(x\text-\)axis |
| 4. | \(16~\text{V/m},\) along the positive \(x\text-\)axis |
Which of the following statements is correct regarding the electrostatics of conductors?
| 1. | The interior of the conductor with no cavity can have no excess charge in the static situation. |
| 2. | The electrostatic potential is constant throughout the volume of the conductor. |
| 3. | The electrostatic potential has the same value inside as that on its surface. |
| 4. | All of the above statements are correct. |
Two capacitors of capacity \(2~\mu\text{F}\) and \(3~\mu\text{F}\) are charged to the same potential difference of \(6~\text V.\) Now they are connected with opposite polarity as shown. After closing switches \(S_1~\text{and}~S_2\), their final potential difference becomes:
| 1. | \(\text{zero} \) | 2. | \(\frac{4}{3}~\text{V} \) |
| 3. | \(3~\text{V} \) | 4. | \(\frac{6}{5}~\text{V} \) |
© 2025 GoodEd Technologies Pvt. Ltd.