Commercially available computer boards for standard applications (say, a PC) dissipate heat and malfunction when they overheat, typically when their temperature exceeds 70°C. Assume that you have a circuit board

with a surface area equal to 70 cm? and the board is going to be cooled by blowing air at20°C parallel to the board surface. Use the information on page 93 of your textbook to determine the maximum and minimum heat transfer rates by convection. For purpose of analysis, you may assume that the surface of the board can be approximated as a flat horizontal surface.