Electrostatics ...

ABC is a right angled triangle in which AB = 3 cm and BC = 4 cm and ∠ABC = π / 2. The three charges +15, +12 and –20 e.s.u. are placed respectively on A, B and C. The force acting on B is

Two charges q₁ and q₂ are placed in vacuum at a distance d and the force acting between them is F. If a medium of dielectric constant 4 is introduced between them, the force now will be

Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then

A force F acts between sodium and chlorine ions of salt (sodium chloride) when put 1 cm apart in air. The permittivity of air and dielectric constant of water are ɛ₀ and K respectively. When a piece of salt is put in water electrical force acting between sodium and chlorine ions 1 cm apart is

Two identical charges repel each other with a force equal to 10 mg wt when they are 0.6 m apart in air. (g = 10 ms^–2). The value of each charge is

The value of electric permittivity of free space is

Two similar spheres having +q and –q charge are kept at a certain distance. F force acts between the two. If in the middle of two spheres, another similar sphere having +q charge is kept, then it experience a force in magnitude and direction as

A charge Q is divided into two parts of q and Q – q. If the coulomb repulsion between them when they are separated is to be maximum, the ratio of Q/q should be