Since charge q is distributedon metallic plate, so the charge distributes as q/2 & q/2
=>
= q/2A
Now E due to metallic face =
/
0
By induction of charge -q/2 E due to adjacent face on other metallic plate
E = -
/
0
=> E on either side of of plate =
/
0 -
/
0 = 0
E between plates =
/
0 +
/
0 = 2
/
0