Can somebody clarify the following statement:
Two plates, with the same but opposite charge, are placed opposite each other. The electric field between them is equal to σ/2εo - (-σ/2εo) = σ/εo However, the electric field outside of the space between the two plates, for example at point A, located halfway the positive plate, is equal to σ/2εo - σ/2εo = 0.
There is no drawing to illustrate the statement.
I know the formula σ/2εo + σ/2εo = σ/εo, and understand how this can be bent into σ/2εo - (-σ/2εo) = σ/εo, as they are opposite charges, and need to be added, as they reinforce each other.
However, I am lost as to σ/2εo - σ/2εo = 0 for the external point. Could somebody clarify the latter bit?