Charge Behaviour

Q.

A point charge of +12$\text{μC}$ is at a distance $6\text{cm}$ vertically above the centre of a square of side $12\text{cm}$ as shown in figure. The magnitude of the electric flux through the square will be $\times {10}^3{\text{Nm}}^2/\text{C}$

Q.

While charging a metallic sphere negatively by induction by bringing a positively charged rod near it the electrons will flow from the ground to the sphere when the sphere is connected to the ground with a wire. WHY DOES THIS HAPPEN?

Q. Five balls numbered 1 to 5 are suspended using separate threads. Pairs (1, 2), (2, 4) and (4, 1) show electrostatic attraction, while pair (2, 3) and (4, 5) show repulsion. Therefore ball 1 must be

1. Positively charged
2. Negatively charged
3. Neutral
4. Made of metal

Q. A spherical capacitor consists of two concentric spherical conductors, held in position by suitable insulating supports as shown in figure. The capacitance C, of this spherical capacitor is:

1. $\frac{4\pi {ϵ}_0(r_2-r_1)}{r_1{r}_2}$
2. $\frac{(r_1-r_2)}{4\pi {ϵ}_0{r}_1{r}_2}$
3. $\frac{4\pi {ϵ}_0{r}_1{r}_2}{r_1-r_2}$
4. $\frac{r_1{r}_2}{4\pi {ϵ}_0(r_2-r_1)}$

Q. If the electric potential of the inner shell is $10\text{V}$ and that of the outer shell is $5\text{V}$, then the potential at the centre will be

1. $10\text{V}$
2. $5\text{V}$
3. $15\text{V}$
4. Zero

Q. The charge per unit length of the four quadrant of the ring is $2\lambda ,-2\lambda ,\lambda$ and $-\lambda$ respectively. Find the electric field at the centre.

1. $\frac{2k\lambda }{R}(-\hat{j})$
2. $\frac{2k\lambda }{R}(-\hat{i})$
3. $\frac{2k\lambda }{R}\left(\hat{i}\right)$
4. $\frac{2k\lambda }{R}\left(\hat{j}\right)$

Q. Figure shows, in cross section, two solid spheres with uniformly distributed charge throughout their volumes. Each has radius $R$, Point $P$ lies on a line connecting the centres of the spheres, at radial distance $R/2$ from the centre of sphere $1$. If the net electric field at point $P$ is zero and $Q_1$ is $64\mu \text{C}$. What is $Q_2$ in $\mu \text{C}$

Q. Two equal point charges are fixed at x = -aand x = +aon the x-axis. Another point charge Q is placed at the origin. The Change in the electrical potential energy of Q, when it is displaced by a small distance xalong the x-axis, is approximately proportional to

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

Q.

What is the additive nature of charge?

Q.

Two identical conducting spheres, one having an initial charge +Q and the other initially uncharged, are brought into contact.

1. What is the new charge on each sphere?

2. While the spheres are in contact, a positively charged rod is moved close to one sphere, causing a redistribution of charges on the two spheres, so the charge on the sphere closest to the rod has a charge - Q. What is the charge in the other sphere?

Q. A soap bubble is given a negative charge, then its radius

1. Decreases
2. Increases
3. Remains unchanged
4. Nothing can be predicted as information is insufficient

Q.

Objects A, B and C are three identical, spherical conductors. Originally A and B both have charges of +3 mC, while C has a charge of –6 mC. Object A and C are allowed to touch, then they are moved apart. Then objects B and C are allowed to touch, and they are moved apart.

If Object A and B are now held near each other, they will

1. attract

2. repel

3. have no effect on each other

4. First attract to a certain position then repel

Q.

The dimensions of an atom are of the order of an Angstrom. Thus, there must be large electric fields between the protons and electrons. Why, then is the electrostatic field inside a conductor zero?

Q. A uniformly charged rod of length $4\text{cm}$ and linear charge density $\lambda =30\mu \text{C/m}$ is placed as shown in figure. Calculate the $x-$component of electric field at point $\text{P}$.

1. $36\times {10}^5\text{N/C}$
2. $9\times {10}^5\text{N/C}$
3. $1.8\times {10}^3\text{N/C}$
4. $27\times {10}^5\text{N/C}$

Q.

A body can be negatively charged by

1. Giving excess of electrons to it

2. Removing some neutrons from it

3. Removing some electrons from it

4. Giving some protons to it

Q.

State the different ways by which an object can be charged.

Q.

The extra charge flowing through the cell on closing the key $k$ is equal to

Q.

Name and define the SI unit of current.

Q.

Is a positively charged body attracted by a neutrally charged body to the same extent as a negatively charged body?

Q.

When the cap of a positively charged gold leaf electroscope is brought in contact with a charged rod, the leaves of gold leaf electroscope collapse. What can be concluded about the charge on the rod?

1. positive

2. negative

3. zero

4. information is not sufficient

Q.

Is there a magnetic field inside a conductor?

Q. Mention any 3 fundamental forces in nature

Q. A point charge $Q$ is located at the centre of a cube of edge length $a$. The total electric flux through one of the face of the cube is

1. $\frac{Q}{{\epsilon }_o}$
2. $\frac{Q}{3{\epsilon }_o}$
3. $\frac{Q}{6{\epsilon }_o}$
4. $\frac{3Q}{{\epsilon }_o}$

Q.

What is another word for electric charge?

Q. A metal sphere with its centre at A and radius R has a charge 2q on it. The field at a point B outside the sphere is E. If another metal sphere of radius 3R and having a charge -3q is placed with its cnetre at point B, then resultant electric field at a point mid way between A and B will be

1. 0.5E
2. 2E
3. 2.5E
4. 10E

Q. Two isolated spherical conductors have radii $5\text{cm}$ and $10\text{cm}$ respectively. They have charges of $12\mu \text{C}$ and $-3\mu \text{C}$. Find the charge on bigger sphere after they are connected by a conducting wire.

1. $6\mu \text{C}$
2. $3\mu \text{C}$
3. $9\mu \text{C}$
4. $4\mu \text{C}$

Q.

How to find after rubbing which all particles will have positive charges and which all will have negative charges while such questions are given in exams?

Nb: Without electroscope.

Q. Four point charges, each –q are placed at the corners of a square and another charge Q is placed at its centre. If the system is in equilibrium, then Q is

1. $-\frac{q}{4}[1+2\sqrt{2}]$
2. $-\frac{q}{4}[1+2\sqrt{2}]$
3. $-\frac{q}{2}[1+2\sqrt{2}]$
4. $-\frac{q}{2}[1+2\sqrt{2}]$

Q.

The rubbed insulators able to retain charges placed on them so they were called dielectrics and rub conductors could not retain charges placed on them but immediately drained away the charges so they were called non electric I want to know the reason for this please explain me

Q. Charged particle moves along a circle under possible constant electric and magnetic fields. What is possible?

1. E=0, B=0
2. E=0, B not equals to 0
3. E not equals to 0, B = 0
4. E not equals to 0, B not equals to 0