Question

Find the final temperature of a copper rod. Whose area of cross-section changes from 10 m² to 11 m² due to heating. The copper rod is initially kept at 90K. (Coefficient of superficial expansion is 0.0021 /K)

Answer 1

Given:
Area of copper rod A₀ = A₁ = 10 m2
Changes of area cross-section ∆A = A₂ – A₁ = 11 – 10 = 1 m²
Initial temperature t₁ = 90 K
∆T = t₂ – t₁ = t₂ – 90
Coefficient of superficial expansion α_A = 0.0021 / K Then t₂ = ?

Element	No. of Protons	No. of Neutrons	Mass Number	Stable Isotopes (abundance)	Atomic Mass (amu)
	7			N - 14 (99.6%)
		8		N - 15 (0.4%)
Silicon	14		28	Si - 28 (92.2%)
	14			Si - 29 (4.7%)
		16		Si - 30 (3.1%)
	17			CI - 35 (75%)
	17			CI - 37 (25%)