Calculate thermal conductance for radial flow of an annular cylinder of length `l` and inner and outer radius `r_(1)` and `r_(2)`. Assume that thermal conductivity of the material is `K`

Answer

`(2pilK)/(ln(r_(2)//r_(1)))`

Explanation

`int dR = overset(r_(2))underset(r_(1))int (dr)/(2pi rl k)`

Solving `R = (ln r_(2)//r_(1))/(2pilk) G = (1)/(R )`