Electric fields between two parallel plates are uniform in strength except at the edges. Millikan determined the charge on a single electron using his famous oil-drop experiment. All charge changes result from the movement of electrons not protons. The direction of a magnetic field is defined by the direction a compass needle points. Magnetic fields point from the north to the south outside the magnet and south to north inside the magnet.
Magnetic flux is measured in webers.
Left hands are for negative charges and Right hands are for positive charges. Solenoids are stronger with more current or more wire turns or adding a soft iron core. Wave Phenomena Sound waves are longitudinal and mechanical. All angles in wave theory problems are measured to the normal . Blue light has more energy.