Write the vector form of force acting between two charges `q_1` and `q_2` having `vec r_1` and `vec r_2` as their position vectors respectively.

The force acting between two point charges q_1 and q_2 kept at the same distance apart in air is attractive or repulsive when q_1q_2<0 .

Deduce an expression for the electric field vecE due to a system of two harges q_1 and q_2 with position vectors vecr_1 and vecr_2 at a oint vecr w.r.t the common origin O.

The force acting between two point charges q_1 and q_2 kept at the same distance apart in air is attractive or repulsive when q_1q_2 > 0 .

If θ is the angle between two proper vectors vec a and vec b , then vec a*vec b lt 0 then

If the position vector of a point A is vec a + 2 vec b and vec a divides AB in the ratio 2:3 , then the position vector of B, is

Two copper shperes of radii r_1 and r_2 having charges q_1 and q_2 are connected by means of a wire. What is the electrical condition that no charge flows between them?