Two parallel plates have equal and opposite charges. When the space between the plates is evacuted, the electric field is `E_0=3.20xx10^5V//m`. When the space is filled with electric the electric field is `E-2.50xx10^5V//m`
a. What is the dielectric constant?
b. What is the charge density on each surface of the dielectric?

Explanation

a. `K=E_0/E=(3.20xx10^5)/(2.50xx10^5)`
`=1.28`
b. `sigma_i=sigma_0(1-1/K)`
`=(E_0epsilon_0)(1-1/K)`
`=(93.20xx10^5)(8.86xx10^-12)(1-1/1.28)`
`=6.2xx10^-7C//m^2`