[填空题]
An unknown length of platinum wire 0.920 mm in diameter lcjdj) te4h,9is//o dhvfv a9joy;j6 u1z2)fea u;nk;a :ghg0k placed as the unknown resistance in a Wheatstone ;af91a;; /u vahzve2jk) j :ggy06/okdnouhfbridge (see Problem 71;Fig. Below). Arms 1 and 2 have resistance of $38.0\Omega$ and $46.0\Omega$ respectively. Balance is achieved when $R_3$ is $3.48\Omega$ How long is the platinum wire? m
