Consider a rectangular cavity with rigid walls of dimensions 0.1mx0.22mx 0.35m. The cavity is filled with air (c = 343m/s). A finite element model is used to determine the natural frequencies and mode shapes of the cavity. A mesh based on parallelepipeds (rectangular cuboids) of equal size l l l is used to discretize the domain. Assume that the objective is to use the finite element model to predict with high precision (error of less than 2%) the natural frequency of model = 3, m = 2, n = 3 of the cavity. 1) What the wavelengths in x, y and z directions for model = 3, m = 2, n = 3? 2) Determine the upper limits for lx, ly, lz required to achieve the desired accuracy for that mode (i.e, choose lx = x...). 10'