CBSE Class 12science Physics Electric Charges and Fields

explain coulambs law give unit and dimensions of electrostatics constant and coulambs law in vector form with superposition principle
 calculate column b force between alpha particles separated by a distance of 3.2 into 10 to the power minus 15 m in air
 Two similar spheres having +Q and Q charges at a kept distance . F force act on between two.if at the middle of the two sphere another similar sphere having +Q is kept then it experience a force in magnitude and direction as
 what is dielectric current
 There is one charged tiny spherical oil drop and the magnitude of electric field intensity at a point on its surface is E. If n such drops are combined to make a single drop then what will be the net electric field intensity at a point on the surface of the bigger spherical drop. Assume that charge is uniformly distributed over the volume of oil drop.
 the force between two charges at distance r is f what will be the force between these charges if the distance between them is doubled and charges are placed in a medium of dielectric constant 10 ?
 A point charge qa = + 100 c is placed at point a (1, 0, 2) m and another point charge qb = +200c isplaced at point b (4, 4, 2) m. Find :(i) magnitude of electrostatic interaction force acting between them(ii) find a f(force on a due to
 Two identical metal spheres have charges +15μC and +25μC areseparated by a distance. If the spheres are first brought into contact and then separated to the original distance, then the ratio of the new force to the previous force is
 Two equal small spheres each weighing 1g , hang by two equal silk threads from the same point. The spheres are charged when in contact and come to rest with their centres 2cm apart and 20cm vertically below the point of support. Find the charge on each sphere.

two bodies of masses m,2m and charges q and 2q ,q is hanged with two strings of equal length 'l' as shown. which one of the following is correct.