In the Niagara Falls hydroelectric generating plant, the energy of falling water is converted into electricity. The height of the falls is about 48 meters. Assuming that the energy conversion is highly efficient, approximately how much energy is obtained from one kilogram of falling water

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =