What's an impure potassium carbonate

Two large, flat, horizontally oriented plates are parallel to each other, a distance d apart. half way betwween the two plates the electric field has magnitude e. if the separation of the plates is reduced to d/2 what is the magnitude of the electric field half way between the plates?

State the right hand rule of the direction of magnetic field in a conductor carrying current

How have the competing explanations' experiments on atoms affected the development of the atomic model?