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