This plates-and-voltage lesson treats two ideal parallel plates as a clean way to turn a voltage difference into a central electric field. The arithmetic is exact only for the stated 3 m gap, 12 V input, and ideal uniform-field diagram. Real plates have finite size, edge fringing, dielectric effects, probe calibration limits, finite precision, and measurement uncertainty.
Ideal parallel plates make a clean field case where voltage divided by distance gives the central field. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Place two ideal plates
Two ideal plates separated by 3 metres have a central region where the field is uniform.
d=3m
Apply a voltage
A voltage of 12 volts across the gap sets the field strength.
V=12V
More voltage makes a stronger field
Hold the plate gap at 3 metres. The ideal central field grows in direct proportion to the applied voltage. The diagram shows the middle row.