An ideal gas of density ρ=0.2 kg m⁻³ enters an insulated chimney of height h at 0.8 kg s⁻¹. A₁=0.1 m² and A₂=0.4 m². At the lower end p₁=600 Pa and T₁=300 K; at the upper end T₂=150 K. The expansion is adiabatic, γ=2, g=10 m s⁻², and atmospheric pressure is ignored. Which statement(s) is(are) correct?