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A current of 4 A flows through a nichrome wire under a P.D. of 4V. If the length of the nichrome wire is 1 m andits area of cross section is 1 mm², then its resistivity is(a) 2 x 10-6 m (b) 2 x 10-72m(C) 10-62 m(d) 5 x 10-722-m |
| Answer» RESISTANCE of the WIRE R=IV∴ R=42=0.5ACross-section AREA of wire A=1mm 2=10−6m2Length of wire L=1mThus RESISTIVITY of wire ρ=LRA∴ ρ=10.5×10−6=5×10−7Ωm | |