**Solution (b):**** Given:** Constant pressure, P = 1.01 × 10^{5} Pa

^{ }Δu = 4.50 × 10^{3} J, ΔQ = 7.50 × 10^{3} J

**Required:** Change in volume, ΔV

**Formulae:** ΔQ = Δu + ΔW … (1)

For constant pressure process, ΔW = PΔV … (2)

**Calculation:** Put value of ΔW in the first formula, ΔQ = Δu + PΔV. Now put given values in this equation,