Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and magnitude `17.0xx10^(-22)Cm^(-2)`. What is the electric field
a. in the outer region of the first and the second plates?
b. between the plates?

Explanation

a. Electric field in the regiion 1 is
`E_(1)=vecE_(A)+vecE_(B)`
`=+(sigma)/(2 epsilon_(0))-(sigma)/(2 epsilon_(0))=0`

b. Electric fiedl in the region (3) is
`E_(3)=E_(A)+E_(B)=(sigma)/(2 epsilon_(0))-(sigma)/(2epsilon_(0))=0`
c. Electric field in the region (2) is
`E_(2)=(sigma)/(2 epsilon_(0))+(sigma)/(2 epsilon_(0))=(sigma)/(epsilon_(0))`
i.e. `E_(2)=(17.0xx10^(-22))/(8.854xx10^(-12))=1.92xx10^(-10)NC^(-1)`
Thus electrif is field in between the plates `=1.92xx10^(-10)NC^(-1)`