Two copper wires are joined in series

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

Two copper wires are joined in series. Wire A is 2 m2\,\text{m} long with a cross-sectional area of 1 mm21\,\text{mm}^2, and Wire B is 3 m3\,\text{m} long with an area of 0.5 mm20.5\,\text{mm}^2. If the resistivity of copper is 1.6×10−8 Ω m1.6\times10^{-8}\,\Omega\,\text{m}, the total resistance between the free ends of the combination is closest to (a) 0.024 Ω0.024\,\Omega (b) 0.064 Ω0.064\,\Omega (c) 0.128 Ω0.128\,\Omega (d) 0.160 Ω0.160\,\Omega

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