Q. No.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
In a region, the potential is represented by V(x,y,z)=6x-8xy-8y+6yz, where V is in volts and x,y,z are in meters. The electric force experienced by a charge of 2 coulomb situated at point (1,1,1) is
(1)6√5N
(2)30N
(3)24N
(4)4√35N
\(A,B\) and \(C\) are three points in a uniform electric field. The electric potential is:
| 1. | maximum at \(A\) |
| 2. | maximum at \(B\) |
| 3. | maximum at \(C\) |
| 4. | same at all the three points \(A,B\) and \(C\) |
Four point charges are placed, one at each corner of the square.The relation between Q and q for which the potential at the centre of the square is zero, is
(1) Q=-q
(2)Q=-
(3)Q=q
(4)Q=
Two metallic spheres of radii \(1\) cm and \(3\) cm are given charges of \(-1\times 10^{-2}~\text{C}\) and \(5\times 10^{-2}~\text{C},\) respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is:
1. \(2\times 10^{-2}~\text{C}\)
2. \(3\times 10^{-2}~\text{C}\)
3. \(4\times 10^{-2}~\text{C}\)
4. \(1\times 10^{-2}~\text{C}\)
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 \(A(\text{m}^2)\), the energy (joule) stored in the condenser is:
| 1. | \(\dfrac{1}{2}\varepsilon_0 E^2\) | 2. | \(\varepsilon_0 EAd\) |
| 3. | \(\dfrac{1}{2}\varepsilon_0 E^2Ad\) | 4. | \(\dfrac{E^2Ad}{\varepsilon_0}\) |
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