單項(xiàng)選擇題

The resistance of a conductor varies ()

A.directly as its length and inversely as its cross-sectional area
B.inversely as its length and directly as its cross-sectional area
C.directly as its length and directly as its cross-sectional area
D.inversely as its length and inversely as its cross-sectional area

微信掃碼免費(fèi)搜題