Two large thin metal plates are parallel and close to each other on their inner faces the plates have surface charges densites of opposite region of the first plate (b) in the outer region of the second plate and (c ) between the plates

Explanation

Consider two extremely large parallel metallic plate-1 and plate-2.
For plate-1, its inner face a, b, c, d has charge `q = sigmaA`. Its outer face e, f, g, h has no charge. Hence, on the left of plate-1, E = 0.
Here, electric field produced by positively charged inner face is,
`E_(1) (to) = sigma/(2epsilon_(0))`...........(1)
For plate-2, charge on its inner face `a_(2), b_(2), c_(2), d_(2)` has charge `q =- sigmaA` . Its outer face `e_2, f_2, g_2, h_2` has no charge. Hence, on the right of plate-2, E = 0.
Here electric field produced by negatively charged inner face is,
`E_(2)(to) = sigma/(2epsilon_(0))`...........(2)
Now, resultant electric field between the plates is:
`E = E_(1) + E_(2), (therefore vecE_(1) || vecE_(2))`
`=sigma/(2epsilon_(0)) + sigma/(2epsilon_(0))`
`=sigma/(epsilon_(0))`
`=(17 xx 10^(-22))/(8.85 xx 10^(-12))`
`therefore E = 1.92 xx 10^(-10) N//C`