Thermodynamics · Paper 2 — Free Physics HL Practice Questions

A Stirling engine operates with $n = 0.040\,\text{mol}$ of an ideal monatomic gas undergoing four processes per cycle: - $1 \to 2$: Isothermal compression at $T_c = 350\,\text{K}$, volume from $V_1 = 2.0 \times 10^{-3}\,\text{m}^3$ to $V_2 = 1.0 \times 10^{-3}\,\text{m}^3$ - $2 \to 3$: Isochoric heating from $350\,\text{K}$ to $T_h = 650\,\text{K}$ - $3 \to 4$: Isothermal expansion at $T_h = 650\,\text{K}$, volume from $1.0 \times 10^{-3}\,\text{m}^3$ to $2.0 \times 10^{-3}\,\text{m}^3$ - $4 \to 1$: Isochoric cooling from $650\,\text{K}$ to $350\,\text{K}$ Use $R = 8.31\,\text{J\,mol}^{-1}\text{K}^{-1}$ and isothermal work $W = nRT\ln\!\left(\dfrac{V_f}{V_i}\right)$.