Inserting metal to parallel plate capacitor

[K.z_z]

If there is a parallel plate capacitor with plate area, A, plate separation, d, and a slab of copper of thickness, b, is inserted exactly halfway between the plates. How to find it's new capacitance, C', and new potential difference, V' ?

Answer: V' = E(d-b) and C' = εA / (d-b)

I understand that there would be no effect on the electric field and E = Vd, and there is no electric field inside the copper. Is this why we exclude the thickness of the copper when calculating V' ? And why also do the same for capacitance? Thank you

 

[NascentOxygen]

It is the same as having 2 capacitors in series, each having one of the narrow air gaps as its own, and the sides of the metal insert forming a plate for each of the new capacitors. Yes, there is no voltage gradient across the copper.

 

[K.z_z]

thank you so much. I understand it.