Consider a uniform metallic wire of resistance R. If the wire is stretched uniformly to twice its original length without changing its mass, what will be the new resistance of the wire?

💡 Solution & Explanation

When a wire is stretched to twice its length, its cross-sectional area decreases by a factor of two to maintain constant volume. Since electrical resistance is directly proportional to length and inversely proportional to cross-sectional area, doubling the length while halving the area increases the resistance by a factor of four. Resistivity is an intrinsic property of the material and does not change upon stretching.