The pressure of a gas changes linearly with volume from A to B as shown in figure. If no heat is supplied to or extracted from the gas then change in the internal energy of the gas will be:

Question

G1 Physics · Accepted Answer

Since Q = 0, ΔU = -W. From the P–V graph, average pressure during compression is 30 kPa and |ΔV| = 150 cm³ = 150×10⁻⁶ m³. Work done by gas W = -30×10³×150×10⁻⁶ = -4.5 J. Hence ΔU = +4.5 J.