Electrostatic Shielding

Q.

In a medium the force of attraction between two point electric charges, distance r apart, is F. What distance apart should these be kept in the same medium so that the force between them becomes 3F?

1. 3r

2. r/4

3. 

4. r/3

Q.

Why is electric field intensity inside a charged conductor zero?

Q.

Why should electrostatic field be zero inside a conductor?

Q.

Can an electric field inside a conductor be non-zero?

Q. A positive point charge $Q$ is kept (as shown in the figure) inside a neutral conducting shell whose centre is at $C$. An external uniform electric field $E$ is applied. Then

1. force on $Q$ due to $E$ is zero.
2. net force on $Q$ is zero
3. net force acting on $Q$ and conducting shell considered as a system is zero
4. net force acting on the shell due to $E$ is zero

Q. The figure shows a charge q placed inside a cavity in an uncharged conductor. Now if an external electric field is switched on:

1. Only induced charge on inner surface will redistribute.

2. Only induced charge on outer surface will redistribute

3. Both induced charge on outer and inner surface will redistribute.

4. Force on charge q placed inside the cavity will change.

Q. Figure shows a neutral conductor (spherical shape) having a random shaped cavity. A charge $Q$ is placed in the cavity. Choose the correct statement(s).

1. Electric field due to induced charges on ${\text{S}}_1$ and $Q$ is Non-zero at point $\text{P}$.
2. The induced charges appearing on ${\text{S}}_1$ are uniformly distributed.
3. The induced charges appearing on ${\text{S}}_1$ are non-uniformly distributed.
4. The charges appearing on ${\text{S}}_2$ are uniformly distributed.

Q. Figure shows a conductor with cavity inside it. Charge Q is kept inside cavity. a, b and c are 3 points as shown in figure. Choose the correct option(s).

1. Field at point 'a' due to induced charges is zero.
2. Field at point 'b' due to induced charges is zero.
3. Field at point 'c' due to induced charges on outer surface of conductor is zero.
4. Field at point 'a' due to Q and induced charges on inner surface of conductor is zero.

Q. Force between two charges placed at a distance r in vacuum is F .Now a dielectric slab of K =4 is inserted between them .its thickness is r/2.The new force between the charges F/4 F/2. 3F/5. 4F/9.

Q.

Why is there no electric field at the center of a charged spherical conductor?

Q.

What Is Hollow Conductor?

Q.

A charge q placed inside a metal box. Another charge Q is brought near the box, but outside it. The force felt by charge q due to charge Q will be zero.

1. True

2. False

Q. A charge q is placed at the centre of the open end of a cylindrical vessel as shown in figure. The flux of the electric field through the surface of the vessel is :

1. zero
2. $\frac{q}{{\epsilon }_0}$
3. $\frac{q}{2{\epsilon }_0}$
4. $\frac{2q}{{\epsilon }_0}$

Q.

What ions must be present in a solution used for electroplating a particular metal?

Q.

Paragraph for below question
नीचे दिये गये प्रश्न के लिए अनुच्छेद

A parallel plate capacitor consists of two large plane parallel conducting plates separated by a small distance. The introduction of dielectric medium between the plates of capacitor increases its capacity. The electric field between plates is uniform and outside the plates, electric field is zero.

The capacity of such capacitor depends on dimensions of capacitor plates, plate separation and intervening medium. With this information, answer the following question.

एक समांतर प्लेट संधारित्र, अल्प दूरी द्वारा पृथक्कृत दो बड़ी समतल समांतर चालक प्लेटों से मिलकर बना है। संधारित्र की प्लेटों के मध्य परावैद्युत माध्यम प्रवेशित करने पर, इसकी धारिता बढ़ती है। प्लेटों के मध्य विद्युत क्षेत्र एकसमान है तथा प्लेटों के बाहर विद्युत क्षेत्र शून्य है।

ऐसे संधारित्रों की धारिता संधारित्र की प्लेटों की विमाओं, प्लेटों के मध्य दूरी तथा प्लेटों के बीच के माध्यम पर निर्भर करती है। इस सूचना के आधार पर, निम्नलिखित प्रश्न का उत्तर दीजिए।

Q. A parallel plate capacitor has capacity C₀. The separation between the plates is doubled and a dielectric slab is fully inserted between the plates. If the capacity becomes 5C₀, the dielectric constant of the medium will be

प्रश्न - एक समांतर प्लेट संधारित्र की धारिता C₀ है। प्लेटों के मध्य दूरी दोगुनी की जाती है तथा प्लेटों के मध्य एक परावैद्युत पट्टिका को पूर्णतः प्रवेशित किया जाता है। यदि धारिता 5C₀ हो जाती है, तब माध्यम का परावैद्युतांक होगा

1. 5
2. 2.5
3. 10
4. 0.2

Q. Two point charges $q_1$ and $q_2$ are placed at a distance d apart as shown in the figure. The electric field intensity is zero at the point P on the line joining them as shown .
Write two conclusions that you draw from this.

Q. The net electric field inside an insulator kept in a uniform electric field get

1. Increases
2. Decreases
3. Zero
4. Increases near entery and decreases near exit

Q. In the given question, a statement of Assertion $\left(A\right)$ is given, followed by a corresponding statement of Reason $\left(R\right)$ just below of it. Mark the correct answer.

Assertion$\left(A\right)$ : An uncharged conducting slab is placed normally in a uniform electric field. The resultant electric field inside the slab is zero.

Reason$\left(R\right)$ : The charge in the conductor exists only on its surface

1. Both $\left(A\right)$ and $\left(R\right)$ are true and $\left(R\right)$ is the correct explanation of $\left(A\right)$
2. Both $\left(A\right)$ and $\left(R\right)$ are true and $\left(R\right)$ is not the correct explanation of $\left(A\right)$
3. $\left(A\right)$ is true and $\left(R\right)$ is false
4. $\left(A\right)$ is false and $\left(R\right)$ is true

Q. An insulating hollow cube of side l carries uniform charge on all of its surfaces.the surface charge density is sigma.determime the force acting on the face due to all other faces.

Q. Electromagnetic waves are produced by
(a) a static charge
(b) a moving charge
(c) an accelerating charge
(d) chargeless particles

Q.

Explain the electrostatic shielding

Q. Figure shows a neutral conductor (spherical shape) having a random shaped cavity. A charge $Q$ is placed in the cavity. Choose the correct statement(s).

1. The induced charges appearing on ${\text{S}}_1$ are uniformly distributed.
2. The charges appearing on ${\text{S}}_2$ are uniformly distributed.
3. Electric field due to induced charges on ${\text{S}}_1$ and $Q$ is Non-zero at point $\text{P}$.
4. The induced charges appearing on ${\text{S}}_1$ are non-uniformly distributed.

Q. Conduction electrons are almost uniformly distributed within a conducting plate. When placed in an electrostatic field $\overrightarrow{E}$ the electric field within the plate

1. depends upon E
2. is zero
3. depends upon the atomic number of the conducting element
4. depends upon $\overrightarrow{E}$

Q. A capacitor P is charged by the battery. The charging battery is disconnected. An identical uncharged capacitor is now connected to the first capacitor in parallel. If final energy stored in each capacitor is U, then the initial energy stored in the capacitor P will be

एक संधारित्र P को बैटरी द्वारा आवेशित किया जाता है। आवेशन बैटरी को विच्छेदित किया जाता है। एकसमान अनावेशित संधारित्र को अब प्रथम संधारित्र के समांतर में संयोजित किया जाता है। यदि प्रत्येक संधारित्र में संग्रहित अन्तिम ऊर्जा U है, तब संधारित्र P में संग्रहित प्रारम्भिक ऊर्जा होगी

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

Q. Two concentric conducting shells have uniform charge distribution Q and 2Q. Electric potential at point P as shown in figure is

दो संकेन्द्रीय चालक कोशों पर एकसमान आवेश वितरण Q व 2Q हैं। चित्र में दर्शाए गए बिन्दु P पर विद्युत विभव है

1. $\frac{Q}{4\pi {\epsilon }_0}\frac{1}{r}$
2. $\frac{Q}{4\pi {\epsilon }_0}\left(\frac{1}{r}+\frac{1}{a}\right)$
3. $\frac{Q}{2\pi {\epsilon }_0}\frac{1}{a}$
4. $\frac{Q}{4\pi {\epsilon }_0}\left(\frac{1}{r}+\frac{1}{2a}\right)$

Q. a charged conducting rod of charge Q and length L , a point charge q placed at a distance x from it . Determine net force on point charge .

Q. Two conducting plates X and Y, each with a large surface area A (on one side), are placed parallel to each other, as shown in the figure (30-E7). Plate X is given a charge Q, whereas the other is kept neutral. Find (a) the surface charge density at the inner surface of plate X (b) the electric field at a point to the left of the plates (c) the electric field at a point in between the plates and (d) the electric field at a point to the right of the plates.

Q. Two thin conducting shells of radii $R$ and $2R$ are shown in figure. The outer shell carries a charge $+Q$ and inner shell is neutral. Choose the correct option.

1. With switch open potential of inner sphere is same as that of point at distance $\frac{3R}{2}$ from centre
2. When switch S is closed, potential of inner sphere becomes zero
3. With switch S closed charge on inner sphere is $(-\frac{Q}{2})$
4. With switch S closed charge on inner sphere is $(-Q)$
5. With switch S open charge on inner sphere is $-4Q$
   

Q. A charge Q is placed at a dis†an ce a/2 above the center of a horizontal , square surface of edge a .Find eectric flux through the sqaure surface.

Q.

In di-electric constant and di-electric medium, , whatdoesthis di-electric exactly mean??

and what does induced charge mean??