You are given four slabs of lossless dielectric, all with the same intrinsic impedance, n, known to be different form that of free space. The thickness of each slab 4, where 4, is the wavelength as measured in the slab material. The slabs are to be positioned parallel to ane another, and the combination lies in the path of a uniform plane wave, normally-incident. The slabs are to be arranged such that the air spaces between them are either zero, one-quarter wavelength, or one-half wavelength in thickness. Specify an arrangement of slabs and air spaces such that