What is the simplest relationship between the angular wavenumber k and just one of the other kinematic variables? Express your answer using only one of the other kinematic variables plus constants like π. k = nothing

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e