Question

The density of substance decreases from 10 103 kg/m3 to 7 103 kg/m3 on heating it from 0 c to 100 c. The coefficient of linear expansion of substance is

Answer 1

Answer:

k = 63.9 W/m2 ·K) are heated in a furnace to 850°C and then quenched in a water bath at 50°C for a period of 40 seconds as part of a hardening process. The convection heat transfer coefficient is 650 W/m2 ·K.

Answer 2

Given:

The initial density of the substance = 10×10⁻³ kg/m³

The final density of the substance = 7 ×10⁻³ kg/m³

The initial temperature of the substance = 0° C

The final temperature of the substance is 100 °C

To Find:

The coefficient of linear expansion of the given substance.

Solution:

The relation between coefficient of volume expansion, and densities, and temperature difference is

γ ⇒ Δρ/ (ρΔT) = (Δρ₁ - Δρ₂)/ ρΔθ

γ ⇒ (10 - 7) / 10 × (100-0)

γ = 3 × 10⁻⁴

And relation between cefficient of volume expansion and coefficient of linear expansion

γ = 3α

So, α = γ/3 = 3 × 10⁻⁴ = 10⁻⁴

Hence, the coefficient of linear expansion of the substance is (10⁻⁴).