Polarization Vector

Q.

What is the dielectric constant of water.

Q.

The potential energy at a point due to an electric dipole will be maximum and minimum when the angles between the axis of the dipole and the line joining the point to the dipole are respectively:

1. ${90}^{\circ }$ and ${180}^{\circ }$

2. $0^{\circ }$ and ${90}^{\circ }$

3. ${90}^{\circ }$ and $0^{\circ }$

4. $0^{\circ }$ and ${180}^{\circ }$

Q.

The shape of the equipotential surface for an infinite line charge is _____.

Q. Four capacitors and two sources of e.m.f. are connected as shown in the figure. The potential difference in $\text{volt}$ between the points $\text{a and b}$ is (integer only)

Q.

What is dielectric medium

Q. In the figure shown the plates of a parallel capacitor have unequal charges. Its capacitance is ${}^{\prime }{C}^{\prime },P$ is a point outside the capacitor and close to the plate of charge $-Q$. The distance between the plates is ${}^{\prime }{d}^{\prime }.$

Choose the following correct statement(s)

1. A point charge at point ${}^{\prime }{P}^{\prime }$ will experience electric force due to capacitor
2. The potential difference between the plates will be $\frac{3Q}{2C}$
3. The energy stored in the electric field in the region between the plates is $\frac{9Q^2}{8C}$
4. The force on one plate due to the other plate is $\frac{Q^2}{2\pi {\epsilon }_0{d}^2}$

Q. Voltage rating of a parallel plate capacitor is $500V$. Its dielectric can withstand a maximum electric field of ${10}^{6}V/m$. The plate area is ${10}^{-4}{m}^2$. What is the dielectric constant if the capacitance is $15pF$?
(given ${ϵ}_0=8.86\times {10}^{-12}{C}^2/N{m}^2)$.

1. $3.8$
2. $4.5$
3. $6.2$
4. $8.5$

Q.

Write a relation for polarisation$\overrightarrow{P}$ of a dielectric material in the presence of an external electric field $\overrightarrow{E}$

Q. Four capacitors with capacitance C1= 1 micro F, C2 =1.5 micro F, C3 =2.5 micro F and C4= 5 micro F are connected as shown and are connected to a 30 V source. The potential difference between points a and b is :

Q.

When the angle of contact between a solid and a liquid is ${90}^{\circ }$, then

1. Cohesive force>Adhesive force

2. Cohesive force=Adhesive force

3. Cohesive force<Adhesive force

4. Cohesive force>>Adhesive force

Q.

It is required to construct a 10microF capacitor which can be connected across a 200V battery.Capacitors of capacitance 10microF are available but they can withstand only 50V. Design a combination which can yield the desired result

Q. Three slabs of same dimension having dielectric constants $K_1,K_2$ and $K_3$ completely fill the space between the plates of a parallel plate capacitor as shown in figure. If $C$ is the initial capacitance of the capacitor, the new capacitance after the introduction of slabs will be:

1. $\left(\frac{K_1{K}_2}{K_1+K_2}\right)C$
2. $\left(\frac{K_1+K_2+K_3}{3}\right)C$
3. $(K_1+K_2)C$
4. $\left(\frac{K_1+K_2}{2}\right)C$

Q. A dielectric sphere is placed in uniform electric field $\overrightarrow{E}$ as shown in figure. AB = BC = 2R. $E_A,E_B$ and $E_C$ are electric field at A, B and C respectively, then

1. $E_A>E_B>E_C$
2. $E_A=E_B=E_C$
3. $E_B=0,E_A=E_C$
4. $E_A=E_C>E_B$

Q. The figure illustrate how B, the flux density inside a sample of unmagnetised ferromagnetic material varies with $B_0$, the magnetic flux density in which the sample is kept. For the sample to be suitable for making a permanent magnet

1. OQ and OR should both be small
2. OQ should be large, OR should be small
3. OQ and OR should both be large
4. OQ should be small and OR should be large

Q. There are 2 concentric spherical conducting shells of radii r and 3r. The outer shell carries a charge q and inner shell is uncharged. Inner shell is now connected with earth find the amount of charge flow from inner shell to the earth.

Q. 56.What is the potential difference between the points M and N for the circuits shown in the figures, for case l and case ll?

Q. A metallic spherical shell has an inner radius Rand outer radius R2. A charge Q is placed at thecentre of the spherical cavity. What will be surfacecharge density on the inner surface and the outersurface?

Q. Find the final potential across the two capacitors, if the initial conditions is as shown below.

1. $\frac{7V}{11}$
2. $\frac{2V}{7}$
3. $\frac{11V}{7}$
4. $\frac{9V}{7}$

Q. Why electric field inside spherical capacitor is zero??

Q. define dielectric strength

Q. Two thin dielectric slabs of dielectric constants $K_1$ and $K_2(K_1<K_2)$ are inserted between plates of a parallel plate capacitor, as shown in figure. The variation of electric field $E$ between the plates with distance $d$ as measured from plate $\text{P}$ is correctly shown by

1. 
2. 
3. 
4. 

Q.

What is permittivity

Q. If the dielectric constant of a substance is $K=\frac{4}{3}$, then the electric susceptibility ${\Psi }_e$ is:

1. $\frac{3}{4}$
2. $3$
3. $\frac{1}{3}$
4. $\frac{4}{3}$

Q.

The unit of Polarization is?

1. $C/m^2$

2. $C/m^3$
3. $C-m^2$
4. $C/m$

Q. Define linear charge density. Mention its $SI$ unit.

Q. A parallel plate capacitor has a dielectric (of dielectric constant $k$) between the plates. The plates are charged to a surface charge density ${\sigma }_0$. What is the density of the polarized charge that appear on the surface of the dielectric.

Q. Read the following and write the correct pairs. Initially, the two plates (A and B) are given charges as shown. Find the final charges on the plates after the key k is closed. All plates are conducting, parallel and of infinite length and breadth.

$\begin{array}{cccc}& \text{List-I}& & \text{List-II}\\ \text{(P)}& \text{Final charge on plate A}& \left(1\right)& \frac{Q}{2}\\ \text{(Q)}& \text{Final charge on plate B}& \left(2\right)& \text{Q}\\ \text{(R)}& \text{Final charge on plate C}& \left(3\right)& \text{0}\\ \text{(S)}& \text{Final charge on plate D}& \left(4\right)& \frac{3Q}{2}\end{array}$
Which of the following option has the correct combination considering column –I and column – II

1. $P\to 3$
2. $Q\to 4$
3. $R\to 1$
4. $S\to 3$

Q. In a common-base configuration a 0.98, lB 0.02 mAand RL = 5 ka, Outpul voltage across load isRL3.2 V4.9 V5.2 V6.2 V

Q. Why was spherical capacitor made, if it has no use?

Q. 7. In the circuit shown in the figure, the potential difference across 10 micro farad capacitor is-