Practice question
Question
A brass rod of length 2m at 25∘C is heated to 125∘C. Calculate the increase in length. (Coefficient of linear expansion of brass = 1.8×10−5K−1)
Explanation
Given: L0 = 2m, ΔT = 125−25 = 100∘C, αl = 1.8×10−5K−1. ΔL = L0αlΔT = 2×1.8×10−5×100 = 3.6×10−3m = 3.6mm. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 3.6 mm. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.