A conducting open pipe has shape of a half cylinder of length L. Its semicircular cross section has radius `r` and thickness of the conducting wall is `t (lt lt r)`. The resistance of the conductor when the current enters and leaves as shown in figure (a) is `R_(1)` and its resistance is `R_(2)` when the current is as shown in figure (b). find `(R_(1))/(R_(2))`

Answer

`(L^(2))/(pi^(2)r^(2))`