How do you find the direction of electric field on the outer or inner surface of 2 parallel plate of a capacitor ?
The direction of electric field is from the positive plate to negative plate.
The electric field outside the plates is zero as the electric field due to each plate (E=Q/2ε0A) cancel out being equal in magnitude and opposite in direction.
In between the plates the two electric fields add up as they are in same direction. (From positive plate to negative plate).
The magnitude of electric field between the plates is twice the electric field due to either; i.e; E=2 x Q/2ε0A = Q/ε0A