The limitations of a microscope or a telescope are due to diffraction. Interference can also occur when we have two close-by surfaces. Diffraction grating has many close-by slits, which magnifies the interference effects. The resolving power of a telescope is limited by diffraction and the larger the objective lens, the better is the resolution. All other charges are multiples of this basic unit of charge.
Electric field is a vector, i.e. it has both magnitude and direction.
The unit is volt . One volt is one joule per coulomb. A conductor allows electrons to pass with little loss of energy. Examples are metals, such as copper. An insulator does not allow electrons to pass through.