Four charges $+Q,-Q,+Q,-Q$ are placed at the corners of a square taken in order. At the centre of the square 

(1) $E=0,V=0$

(2) $E=0,V\ne 0$

(3) $E\ne 0,V=0$

(4) $E=0,V\ne 0$

Point charge q₁ = 2 μC and q₂ = –1 μC are kept at points x = 0 and x = 6 respectively. Electrical potential will be zero at points 

(1) x = 2 and x = 9

(2) x = 1 and x = 5

(3) x = 4 and x = 12

(4) x = –2 and x = 2

Equipotential surfaces associated with an electric field which is increasing in magnitude along the x-direction are 

(1) Planes parallel to yz-plane

(2) Planes parallel to xy-plane

(3) Planes parallel to xz-plane

(4) Coaxial cylinders of increasing radii around the x-axis

A bullet of mass 2 gm is having a charge of 2 μC. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s ?

(1) 5 kV

(2) 50 kV

(3) 5 V

(4) 50 V

In a certain charge distribution, all points having zero potential can be joined by a circle S. Points inside S have positive potential, and points outside S have a negative potential. A positive charge, which is free to move, is placed inside S. What is the correct statement about S:

A square of side ‘a’ has charge Q at its centre and charge ‘q’ at one of the corners. The work required to be done in moving the charge ‘q’ from the corner to the diagonally opposite corner is -

(1) Zero

(2) $\frac{Qq}{4\pi {\in }_{0}a}$

(3) $\frac{Qq\sqrt{2}}{4\pi {\in }_{0}a}$

(4) $\frac{Qq}{2\pi {\in }_{0}a}$

As per this diagram a point charge +q is placed at the origin O. Work done in taking another point charge –Q from the point A [co-ordinates (0, a)] to another point B [co-ordinates (a, 0)] along the straight path AB is

(1) Zero

(2) $\left(\frac{{\displaystyle -qQ}}{{\displaystyle 4\pi {\epsilon }_0}}\frac{{\displaystyle 1}}{{\displaystyle a^2}}\right)\sqrt{2}a$

(3) $\left(\frac{{\displaystyle qQ}}{{\displaystyle 4\pi {\epsilon }_0}}\frac{{\displaystyle 1}}{{\displaystyle a^2}}\right)\frac{a}{\sqrt{2}}$

(4) $\left(\frac{{\displaystyle qQ}}{{\displaystyle 4\pi {\epsilon }_0}}\frac{{\displaystyle 1}}{{\displaystyle a^2}}\right)\sqrt{2}a$

Two charges q₁ and q₂ are placed 30 cm apart, as shown in the figure. A third charge q₃ is moved along the arc of a circle of radius 40 cm from C to D. The change in the potential energy of the system is $\frac{q_3}{4\pi {\epsilon }_0}k$, where k is:

Two thin wire rings each having a radius R are placed at a distance d apart with their axes coinciding. The charges on the two rings are +q and –q. The potential difference between the centres of the two rings is -

(1) Zero

(2) $\frac{Q}{4\pi {\epsilon }_0}\left[\frac{{\displaystyle 1}}{{\displaystyle R}}-\frac{{\displaystyle 1}}{{\displaystyle \sqrt{R^2+d^2}}}\right]$

(3) $QR/4\pi {\epsilon }_0{d}^2$

(4) $\frac{Q}{2\pi {\epsilon }_0}\left[\frac{{\displaystyle 1}}{{\displaystyle R}}-\frac{{\displaystyle 1}}{{\displaystyle \sqrt{R^2+d^2}}}\right]$

A hollow metallic sphere of radius R is given a charge Q. Then the potential at the centre is -

(1) Zero

(2) $\frac{1}{4\pi {\epsilon }_0}.\frac{Q}{R}$

(3) $\frac{1}{4\pi {\epsilon }_0}.\frac{2Q}{R}$

(4) $\frac{1}{4\pi {\epsilon }_0}.\frac{Q}{2R}$