A long copper plate, 4 cm thick and at an ini al temperature of 200C is held out on a water surface so that its one face is in contact with water at 30C. The outer surface is exposed to air at 30C. The heat transfer coefficients on the air and water side are 10 W/m2-K and 100 W/m2-K respec vely. Neglect radia on and heat transfer from edges. Find the me required to cool the plate to a temperature of 100C. Proper es of copper are =8800 kg/m3, cp = 400 J/kg-K, k =360 W/m-K.