1. An opaque gray surface with is irradiated with 1000 W/cm. For an effective convective heat-transfer coefficient of 12 W/m2K applying, and air at 208C adjacent to the plate, what will be the net...

1. An opaque gray surface with

is irradiated with 1000 W/cm. For an effective convective heat-transfer coefficient of 12 W/m²
K applying, and air at 208C adjacent to the plate, what will be the net heat flux to or from a 308C surface?

2. A 7.5-cm-diameter hole is drilled in a 10-cm-thick iron plate. If the plate temperature is 700 K and the surroundings are at 310 K, determine the energy loss through the hole. The hole sides may be considered to be black.