Question

Two infinitely long parallel conducting plates having surface charge densities $+\sigma$ and $-\sigma$ respectively, are separated by a small distance. The medium between the plates is vacuum. If ${ϵ}_0$ is the dielectric permittivity of vacuum, then the electric field in the region between the plates is

• A. 0 volts/meter
• B. $\frac{\sigma }{2{ϵ}_0}$ volts/meter
• C. $\frac{\sigma }{{ϵ}_0}$ volts/meter
• D. $\frac{2\sigma }{{ϵ}_0}$ volts/meter

Answer 1

The correct option is C $\frac{\sigma }{{ϵ}_0}$ volts/meter

Electric field between the plates is
$=\frac{\sigma }{2{ϵ}_0}-\frac{(-\sigma )}{2{ϵ}_0}$
$=\frac{\sigma }{{ϵ}_0}$