Q1. (a) If a slab of meat is to be frozen between refrigerated plates with the plate temperature at -34C, how long will it take to freeze if the slab is 8 cm thick and the meat is wrapped in cardboard 1 mm thick on either side of the slab? Assume that for the plate freezer, the surface heat-transfer coefficient is 500 W.m 2K-2, the thermal conductivity of cardboard is 0.06 Wm-'K-, the thermal conductivity of frozen meat is 1.6 Wim K?, its latent heat is 2.56x10 j.kg and density 1090 kg.m. Assume also that meat freezes at -2C. Employ Plank's model of freezing process. (15 marks] (b) What would be the freezing time if the cardboard were not present? [7 marks) (c) Sketch 3 temperature profiles across the slab corresponding to: #1 - the start of the process, #2 - intermediate state, and #3 - end of freezing of the slab. Consider case (b). [8 marks)