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#thermal expansion

29 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 steel cylinder has a volume of 1.5L at 55∘C. What temperature must it be heated to for the volume to increase by 0.005

Given: V0 = 1.5L = 1500cm3, ΔV = 0.0054L = 5.4cm3, αl = 1.2×10−5K−1, T1 = 55∘C. αv = 3αl = 3×1.2×10−5 = 3.6×10−5K−1. ΔV = V0αvΔT⇒5.4 = 1500×3.6×10−5×ΔT. ΔT = 5.41500×3.6×10−5 = 5.40.054 = 100K. T2 = 55+100 = 155∘C.

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

Which of the following is true about the coefficient of volume expansion compared to the coefficient of linear expansion

The coefficient of volume expansion (αv) is three times the coefficient of linear expansion (αl), as αv = 3αl (Section 10.5). As per NCERT, applying relevant law/formula with correct units and sign convention leads to αv\=3αl. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.

A copper plate has an area of 0.8m2 at 60∘C. What is the decrease in area when cooled to 10∘C? (αl\=1.7×10−5K−1)

Given: A0 = 0.8m2, ΔT = 10−60 = −50∘C, αl = 1.7×10−5K−1. ΔA = A0×2αlΔT = 0.8×2×1.7×10−5×(−50). ΔA = 0.8×3.4×10−5×(−50) = −0.00136m2 (decrease of 0.00136m2). As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.00136 m². This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

A silver ring has an inner circumference of 31.4cm at 15∘C. What temperature must it be heated to for the circumference

Given: L0 = 31.4cm, ΔL = 0.0597cm, αl = 1.9×10−5K−1, T1 = 15∘C. ΔL = L0αlΔT⇒0.0597 = 31.4×1.9×10−5×ΔT. ΔT = 0.059731.4×1.9×10−5 = 0.05975.966×10−4≈100K. T2 = 15+100 = 115∘C. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 115°C. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

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

Why do gases expand more than solids for the same temperature increase?

Gases have a much higher coefficient of volume expansion than solids due to weaker intermolecular forces, allowing greater volume changes with temperature. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Gases have a higher expansion coefficient. This satisfies dimensional consistency and physical conditions given, so option D is scientifically correct.

Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.

A brass rod of length 2m at 25∘C is heated to 125∘C. Calculate the increase in length. (Coefficient of linear expansion

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.

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