The resistance of a wire is directly proportional to its length and inversely proportional to its area of cross-section. Resistances in series add up directly.
A metallic wire having length *l* and area of cross-section A has a resistance R. It is now connected in series with a wire of same metal but with length 2*l* and area of cross-section 2A. The total resistance of the combination will be:
Asked in UPSC Geoscientist 2020 · Topic: Electric Current (Factors affecting resistance (length, area, material, temperature))
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