[填空题]
The wiring in a house must berh 9o2 z4reh,-h 2p(zcrzc ,xr thick enough so it2ihqcer/ 3o6 n does not become so hot as to start a fire. What diameter must a copper wire be if it is to carry a maximum oe6hi3 rq nc/2current of 35 A and produce no more than 1.8 W of heat per meter of length? $ \times10^{ -3}\;m$
