Work done by gas at constant pressure equals pressure times volume change

Steps:

• Work done W = P ΔV, where P is constant pressure and ΔV is change in volume.
• Volume change ΔV = A × Δh, with A as cross-sectional area and Δh as piston displacement.
• Rearrange formula: A = W / (P Δh).
• Substitute given values (W = 11 kJ = 11,000 J, P = 2.0 × 10⁵ Pa, Δh = 2.2 m): A = 11,000 / (2.0 × 10⁵ × 2.2) = 0.025 m² = 2.5 × 10^{-2} m².

Why B is correct:

• Matches calculation from W = P A Δh, the standard formula for constant-pressure expansion work.

Why the others are wrong:

• A: Half the required area, underestimates by factor of 2.
• C: Twice the required area, overestimates by factor of 2.
• D: Four times the required area, overestimates by factor of 4.

Final answer: B