Model Question Paper — 2 — Question 5

Charles law states that pressure remaining constant, the volume of a given mass of dry gas increases or decreases by $\dfrac{1}{273}$ of its volume at 0°C for each 1°C increase or decrease in temperature, respectively.

Mathematical expression of Charles' law :

Suppose, a gas occupies V₁ cm³ at T₁ temperature and V₂ cm³ at T₂ temperature, then by Charles' law:

    V₁ α T₁

or V₁ = kT₁ (k is constant)

or $\dfrac{\text{V}_1}{\text{T}_1}$ = k and

    V₂ α T₂

or $\dfrac{\text{V}_2}{\text{T}_2}$ = k

∴ $\dfrac{\text{V}_1}{\text{T}_1}$ = $\dfrac{\text{V}_2}{\text{T}_2}$ = k (at constant pressure)