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:

1.	the field at B is \(Q \over2ε_0A\)	2.	the field at B is \(Q\overε_0A\)
3.	the fields at A, B and C are of the same magnitude	4.	the fields at A and C are of the same magnitude but in opposite directions

Four charges are arranged at the corners of a square ABCD, as shown in the adjoining figure. The force on the charge kept at the centre O is 

(1) Perpendicular to side BC

(2) Along the diagonal AC

(3) Along the diagonal BD

(4) Perpendicular to side AB

Three charges 4q, Q, and q are in a straight line in the position of 0, l/2, and l respectively. The resultant force on q will be zero if Q = 

(1) – q

(2) –2q

(3) $-\frac{q}{2}$

(4) 4q

Force of attraction between two point charges Q and – Q separated by d meter is F_e. When these charges are placed on two identical spheres of radius R = 0.3 d whose centres are d meter apart, the force of attraction between them is 

(1) Greater than F_e

(2) Equal to F_e

(3) Less than F_e

(4) Less than F_e

When 10¹⁹ electrons are removed from a neutral metal plate, the electric charge on it is 

(1) –1.6 C

(2) +1.6 C

(3) 10⁺¹⁹ C

(4) 10^–19 C

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 particles of equal mass m and charge q are placed at a distance of 16 cm. They do not experience any force. The value of $\frac{q}{m}$ is 

(1) l

(2) $\sqrt{\frac{\pi {\epsilon }_0}{G}}$

(3) $\sqrt{\frac{G}{4\pi {\epsilon }_0}}$

(4) $\sqrt{4\pi {\epsilon }_{0}G}$

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.

ABC is an equilateral triangle. Charges +q are placed at each corner. The electric intensity at O will be 

(1) $\frac{1}{4\pi {\epsilon }_0}\frac{q}{r^2}$

(2) $\frac{1}{4\pi {\epsilon }_0}\frac{q}{r}$

(3) Zero

(4) $\frac{1}{4\pi {\epsilon }_0}\frac{3q}{r^2}$

A charge particle is free to move in an electric field. It will travel 

(1) Always along a line of force

(2) Along a line of force, if its initial velocity is zero

(3) Along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force

(4) None of the above