The given figure shows a cylinder containing fluid with a movable piston. If the piston moves out a small distance ∆x, then the work done by the gas is

Explanation

Work Done by a Gas: In thermodynamics, when a gas expands, it does work on its surroundings. The work done (W) by a gas at constant pressure (P) is given by the formula: W = P * ΔV where ΔV is the change in volume. * Calculating Change in Volume: In the given scenario, the piston has a certain cross-sectional area (let's denote it as 'A') and moves out by a small distance (Δx). The change in volume (ΔV) is therefore the area multiplied by the distance moved: ΔV = A * Δx * Combining for Work Done: Substituting the expression for ΔV into the work formula: W = P * (A * Δx) = pAΔx (using 'p' for pressure as in the options) * Sign Convention: When the gas expands (piston moves out), it is doing positive work. Thus, the work done by the gas should be positive.