A gas expands at constant pressure. The work done by the gas is given by: MCQ with Answer and Explanation

A gas expands at constant pressure. The work done by the gas is given by:
A. P/V
B. Δ(PV)
C. PΔV
D. VΔP
Answer: Option C
Solution (By JKExamLibrary)
For constant pressure (isobaric) process, work done by gas W = PΔV, where ΔV is change in volume. This derives from mechanical work W = F·d and pressure P = F/A, so F = PA, and dV = A·d, thus W = P·dV. Option D Δ(PV) applies to other contexts like enthalpy. Memory tip: 'Isobaric work = P times volume change'. This fundamental thermodynamics result is frequently used in first law applications. Competitive exams often combine this with ideal gas law for numerical problems; always verify process constraints (constant P here).

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