The resultant capacitance across 300 v battery in the figure shown is equal to
(1) 1 μF
(2) μF
(3) 2 μF
(4) μF
A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of the resulting system
1. increases by a factor of 4
2.decreases by a factor of 2
3. remain the same
4. increases by a factor of 2
The diagrams below show regions of equipotentials.
A positive charge is moved from \(\mathrm A\) to \(\mathrm B\) 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). |
An electric dipole is place at an angle of \(30^{\circ}\) with an electric field intensity \(2\times10^{5}~\text{N/C}\). It experiences a torque equal to \(4~\text{Nm}\). The charge on the dipole, if the dipole length is \(2~\text{cm}\), is:
1. | \(8~\text{mC}\) | 2. | \(2~\text{mC}\) |
3. | \(5~\text{mC}\) | 4. | \(7~\mu\text{C}\) |
A parallel-plate capacitor of area A, plate separation d, and capacitance C is filled with four dielectric materials having dielectric constants and as shown in the figure below. If a single dielectric material is to be used to have the same capacitance C in this capacitor, then its dielectric constant k is given by
(a)
(b)
(c)
(d)
A capacitor of \(2~\mu\text{F}\) 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. | \(0\%\) |
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 |
If potential (in volts) in a region is expressed as V(x,y,z)=6xy-y+2yz, the electric field (in N/C) at point (1,1,0) is
(1)-(3+5+3)
(2)-(6+5+2)
(3)-(2+3+)
(4)-(6+9+)
Two thin dielectric slabs of dielectric constants K1&K2 () are inserted between plates of a parallel capacitor, as shown in the figure. The variation of electric field E between the plates with distance d as measured from plate P is correctly shown by
1.
2.
3.
4.
A conducting sphere of radius R is given a charge Q. The electric potential and field at the centre of the sphere respectively are
(a) zero and Q/4πoR2
(b)Q/4πoR and zero
(c)Q/4πoR and Q/4πoR2
(d)Both are zero