Determine the total charge on 75 kg of electrons

The electric field at 2R from the centre of a uniformly charged non-conducting sphere of radius R is E. The electric field at a distance R/2 from the centre will be

Consider three charges q₁, q₂, q₃ each equal to q at the vertices of an equilateral triangle of side l. What is the force on a charge Q (with the same sign as q) placed at the centroid of the triangle?

2 point charges of +16 μC and –9 μC are placed 8 cm apart in air. The Determine the position of the point where resultant electric field is 0 (zero)

State the limitation of Coulomb's law of electrostatics