Coulomb's Law - Practice Questions & MCQ

Two identical charged spheres suspended from a common point by two massless strings of length are initially a distance apart because of their mutual repulsion. The charge begins to leak from both spheres at a constant rate. As a result, the charges approach each other with a velocity . Then the relation between v and x is:

A charge Q is placed at each of the opposite corners of a square. A charge q is placed at each of the other two corners. If the net electrical force on Q is zero, then the Q/q equals

Two spherical conductors B  and C   having equal radii and carrying equal charges in them repel each other with a force  F   when kept apart at some distance.A   third spherical conductor having same radius as that of  B   but uncharged is brought in contact with  B   then brought in contact with   C  and  finally removed away from both, The new force of repulsion between  B  and  C   is  :

Two charges  and  are placed in vacuum at a distance   and the force acting between them is . If a medium of dielectric constant 4 is introduced around them, the force now will be:

A pendulum bob of mass and carrying a charge is at rest in a horizontal uniform electric field of 20000 V/m. The tension in the thread of the pendulum is ( g = 10 m/s²) :

In the given figure two tiny conducting balls of identical mass m and identical charge hang from non-conducting threads of equal length L. Assume that  is so small that, then for equilibrium is equal to