A wire is 1 m long and 1×10−6 m2 in cross-sectional area. When connected to a potential difference of 2 V, a current of 4 A exists in the wire. The resistivity of this wire is: 2×10−6 Ω⋅m 8×10−6 Ω⋅m 1×10−7 Ω⋅m 4×10−7 Ω⋅m 5×10−7 Ω⋅m
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A wire is long and in cross-sectional area. When connected to a potential difference of , a current of exists in the wire. The resistivity of this wire is: