Charge between two metal plates

[Jrlinton]

Homework Statement

Two large metal plates of area 1.1 m^2 face each other, 6.2 cm apart, with equal charge magnitudes but opposite signs. The field magnitude E between them (neglect fringing) is 50 N/C. Find |q|.

Homework Equations

|q|=σA
E=σ/(2Eo)⇒σ=2EoE
|q|=2EoEA

The Attempt at a Solution

I thought that after I did the rearranging of formulas above that this would be a pretty simple problem
|q|=2EoEA
|q|=2(8.99E-9C)(50N/C)(1.1m^2)
|q|=9.889E-7C

 

[haruspex]

Homework Statement

Two large metal plates of area 1.1 m^2 face each other, 6.2 cm apart, with equal charge magnitudes but opposite signs. The field magnitude E between them (neglect fringing) is 50 N/C. Find |q|.

Homework Equations

|q|=σA
E=σ/(2Eo)⇒σ=2EoE
|q|=2EoEA

The Attempt at a Solution

I thought that after I did the rearranging of formulas above that this would be a pretty simple problem
|q|=2EoEA
|q|=2(8.99E-9C)(50N/C)(1.1m^2)
|q|=9.889E-7C

There are two plates.

 

[Jrlinton]

It seems that I used coulombs constant instead of the permittivity of free space