potential difference

Question

If a potential difference of 120 V is applied between the plates of a parallel plate capacitor with air filled between the plates, the surface charge density between the plates becomes 20 nC/cm2. What is the distance between the plates of the capacitor?

Answer 1

Use the equation E = σ / ε^o where E is the electric field intensity, σ the charge density, and ε^o the approximate value of permittivity of air ( 8.854 x 10^-12 C² / Nm² ). As we know ε^o and σ, we can calculate E.

As E = Volts / distance between plates, you can then calculate d.

After changing the surface charge density to C/m², I got 5.3 x 10^-6 for the plate separation. Please let me know if this is the correct answer.