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 $1-$m$-$

long section of the cylinders, determine the rates

of radiation heat transfer between the cylinders

and between the hot cylinder and the

surroundings.answer $212\mathrm{.}8$ W$,679\mathrm{.}9$ W