Charging by Induction

Q.

Two identical metal spheres P and Q are supported on insulating stands and placed in contact. What kind of charges will P and Q develop when a negatively charged ebonite rod is brought near P?

1. P will have a positive charge and Q will have a negative charge

2. P will have a negative charge and Q will have a positive charge

3. Both p and Q will have positive charge

4. Both p and Q will have negative charge

Q. Three charges of $q_1=1\times {10}^{-6}\text{C}$, $q_2=2\times {10}^{-6}\text{C}$ and $q_3=-3\times {10}^{-6}\text{C}$ have been placed as shown. Then, the net electric flux will be maximum for the surface

1. ${\text{S}}_2$
2. ${\text{S}}_1$
3. Same for all three
4. ${\text{S}}_3$

Q. When an uncharged body X is charged by induction from a positively charged body Y, what will be the induced charge on the body X?

1. Negative
2. Postitive
3. The body will be neutral
4. A third kind of charge.

Q. Find the distance of the point from $A$ where the net electric field will be zero for the given configuration.

1. $1.4\text{m}$ towards left
2. $0.4\text{m}$ towards left
3. $2.4\text{m}$ towards left
4. $3.4\text{m}$ towards left

Q. Two charges $q_1$ and $q_2$ are placed $30\text{cm}$ apart as shown in the figure. A third charge $q_3$ is moved along the arc of a circle of radius $40\text{cm}$ from $C$ to $D$. The change in potential energy of the system is $\frac{x{q}_3}{4\pi {ϵ}_0}$ where $x$ is

1. $8q_1$
2. $8q_2$
   
3. $6q_2$
4. $6q_1$

Q. A $2\mu \text{F}$ capacitor is charged to a potential difference of $10\text{V}$. Another $4\mu \text{F}$ capacitor is charged to a potential difference of $20\text{V}$. The two capacitors are then connected in a single loop, with the positive plate of one connected with negative plate of another. What is the amount of heat dissipated in the circuit ?

1. $900\mu \text{J}$
2. $450\mu \text{J}$
3. $600\mu \text{J}$
4. $300\mu \text{J}$

Q.

A photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology in which toner particles are positively charged and then transfer them onto paper in the form of an image/letters.

What charge should the paper possess for this process to happen?

1. Only Positive

2. Only Negative

3. Only Neutral

4. both b and c

Q. A positive point charge $Q$ is brought near an isolated neutral metal cube. Then choose the correct option.

1. The cube becomes negatively charged.
2. The interior remains charge free and the surface of cube gets non-uniform charge distribution
3. The interior becomes positively charged and the surface of cube becomes negatively charged
4. The cube becomes positively charged.

Q. Three point charges $q_1=1\mu \text{C},q_2=-2\mu \text{C}$ and $q_3=3\mu \text{C}$ are placed at $(1\text{m},0,0)$ and $(0,2\text{m},0)$ and $(0,0,3\text{m})$ respectively. The electric potential at origin is

1. $9\times {10}^3\text{J/C}$
2. $3\times {10}^3\text{J/C}$
3. $15\times {10}^3\text{J/C}$
4. $12\times {10}^3\text{J/C}$