A uniform electric field E 0 exists throughout a homogeneous dielectric with permittivity . What is the

A uniform electric field E₀ exists throughout a homogeneous dielectric with permittivity ε. What is the electric field inside a vacuum cavity cut out of the interior of the dielectric in the shape of a rectangular pancake with dimensions L × L × h? Assume that h << L and express E_cav entirely in terms of E₀,ˆn,ε , and ε₀.