Three charges are placed at the vertices of an equilateral triangle of side \(a\) as shown in the following figure. The force experienced by the charge placed at the vertex A in a direction normal to BC is: 

            

1. $Q^2/\left(4\pi {\epsilon }_0{a}^2\right)$

2. $-Q^2/\left(4\pi {\epsilon }_0{a}^2\right)$

3. zero

4. $Q^2/\left(2\pi {\epsilon }_0{a}^2\right)$

Two identical conductors of copper and aluminium are placed in an identical electric field. The magnitude of induced charge in the aluminium will be:

1. zero.

2. greater than in copper.

3. equal to that in copper.

4. less than in copper.

The charge on 500 cc of water due to protons will be: 

Two-point charges, +q and –q are held fixed at (–d, 0) and (d, 0) respectively of an (x, y) coordinate system. Then: 

X and Y are large, parallel conducting plates close to each other. Each face has an area A. X is given a charge Q. Y is without any charge. Points A, B, and C are as shown in the figure. The incorrect option is:

The net dipole moment of the system is of the magnitude:
         

1.  q $\times$ 2a

2.  2q $\times$ 2a

3.  q $\times$ a

4.  2 $\times$ (2q $\times$ 2a)

Two charges 2 $\mathrm{\mu C}$ and 8 $\mathrm{\mu C}$ are separated by 6 cm. The neutral point is at:

The ratio of the electric flux linked with shell \(A\) and shell \(B\) in the diagram shown below is:

An electric dipole is kept at the origin as shown in the diagram. The point A, B, C are on a circular arc with the centre of curvature at the origin. If the electric fields at A, B and C respectively are $\overrightarrow{E_1},$ $\overrightarrow{E_2},$ $\overrightarrow{E_3}$ , then which of the following is incorrect? \(\left ( d\gg l \right )\)

                
1.  $\overrightarrow{E_1}$ $=$ $-\overrightarrow{E_3}$
2.  $\overrightarrow{E_1}$ $=$ $-2\overrightarrow{E_2}$
3.  $\overrightarrow{E_1}$ $=$ $\overrightarrow{E_3}$
4.  $\overrightarrow{E_3}$ $=$ $-\overrightarrow{2E_2}$

A large non-conducting sheet S is given a uniform charge density. Two uncharged small, metal rods A and B are placed near the sheet as shown in the following diagram. Choose the incorrect option:

1.  S attracts A.

2.  S attracts B.

3.  A attracts B.

4.  S repels A.