1. What is the difference between mass and weight?

Weight: how heavy something is
mass: quantity of inertia possessed by and object

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

Number of electron i think