Using the approximate values of convection heat-transfer coefficients given in Table 1-3, estimate the surface temperature for which the free convection heat loss will just equal the radiation heat loss from a vertical 0.3-m-square plate or a 5-cmdiameter cylinder exposed to room air at 20ºC. Assume the surfaces are blackened such that ε = 1.0 and the radiation surrounding temperature may be taken the same as the room air temperature.