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#coefficient of expansion

5 public questions tagged with this topic.

Why does a metallic lid expand more than a glass jar when heated together?

Metals typically have a higher coefficient of linear expansion than glass, causing them to expand more for the same temperature increase. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Metal has a higher coefficient of expansion. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.

Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.

A brass cube of side 15cm at 35∘C is heated to 135∘C. What is the increase in its surface area if one face is 225cm2? (α

Given: A0 = 225cm2 (one face), total surface area = 6×225 = 1350cm2, ΔT = 135−35 = 100∘C, αl = 1.8×10−5K−1. Area expansion: ΔA = A0×2αlΔT. For total surface area: ΔA = 1350×2×1.8×10−5×100 = 1350×3.6×10−3 = 4.86cm2.

Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.