Q$3)$ Two long, parallel $20-cm-$diameter cylinders are located $30cm$ apart from each other. Both cylinders are black and are maintained at temperatures $425K$ and $275K.$ The surroundings can be treated as a blackbody at $300K.$ For a $1-$m$-$long section of the cylinders, determine the rates of radiation heat transfer between the cylinders and between the hot cylinder and the surroundings.