A steel wire and a copper wire have the same length and cross-sectional area. Both are stretched by the same force. If Y
Elongation: ΔL = (F L) / (A Y). Ratio: (ΔLsteel)/(ΔLcopper) = Ycopper / Ysteel = (1.1 × 1011) / (2 × 1011) = 11/20 = 0.55. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.55. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: University Physics, Chapter 17: Thermal Expansion.
