One of the renewable sources of energy is solar energy, which can be used for heating of houses. A solar collector consists of a horizontal pipe made of copper and of the outer diameter 5 cm enclosed in a concentric thin-glass pipe of the diameter 0.12 m. Water is heated as it flows through the pipe, and the annular space between the copper and the glass pipes is filled with air at the atmospheric pressure (=0.003096 K ). The emissivities of the pipe surface and the glass pipe are 0.85 and 0.9, respectively. During a clear day, the temperatures of the pipe surface and the glass pipe are measured to be 333 K and 313 K, respectively. Determine the rate of heat loss from the collector by natural convection and radiation per meter length of the pipe.