[填空题]
The wiring in a house muscs (xpi9tiq2kl:8 9wi li5j/,4nx:g czs, ;9tgmx qiqt be thick enough so it does not become so hot as to start a fire. What diameter must a copper wire be if it is to carry a maximum current of 35 A and produce no more than 1.8 W of heat per meteig5qx;m scglijx/ t:,z9,qn4 r of length? $ \times10^{ -3}\;m$
