The coefficient of areal expansion of a material is 1•6×10⁻⁵ K⁻¹. Whic

The coefficient of areal expansion of a material is 1•6×10⁻⁵ K⁻¹. Which one of the following gives the value of coefficient of volume expansion of this material?

0•8×10⁻⁵ K⁻¹
2•4×10⁻⁵ K⁻¹
3•2×10⁻⁵ K⁻¹
4•8×10⁻⁵ K⁻¹
This question was previously asked in
UPSC NDA-2 – 2018
The value of the coefficient of volume expansion of this material is 2.4×10⁻⁵ K⁻¹.
– For an isotropic solid material, the coefficients of linear expansion (α), areal expansion (β), and volume expansion (γ) are related.
– The relationship is approximately β ≈ 2α and γ ≈ 3α.
– From these relations, we can derive the relationship between the coefficient of areal expansion (β) and the coefficient of volume expansion (γ): γ = (3/2)β.
– Given coefficient of areal expansion β = 1.6 × 10⁻⁵ K⁻¹.
– Substitute the value into the formula: γ = (3/2) * (1.6 × 10⁻⁵ K⁻¹).
– γ = 1.5 * 1.6 × 10⁻⁵ K⁻¹ = 2.4 × 10⁻⁵ K⁻¹.
– These relationships (β=2α, γ=3α) are valid for small changes in temperature and for isotropic materials (materials with the same properties in all directions).
– Linear expansion refers to the change in length, areal expansion to the change in area, and volume expansion to the change in volume per unit change in temperature.
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