Question

For a parallel plate capacitor with no dielectric between its plates, which expression gives the electric field?

Options

• \[E_0=\frac{Q}{\varepsilon_0d}\]

• \[E_0=\frac{\sigma}{\varepsilon_0}=\frac{Q}{\varepsilon_0A}\]

• \[E_0=\frac{\varepsilon_0A}{Q}\]

• \[E_0=\frac{Qd}{\varepsilon_0A}\]

Answer 1

Without a dielectric, the field is the surface charge density divided by vacuum permittivity. Since \[\sigma=Q/A\], it is also \[E_0=Q/(\varepsilon_0A)\].