MHTCET 15 Apr 2026 Shift 1 Paper

Concept:An isobaric process takes place at constant pressure, and the first law of thermodynamics connects heat, work, and internal energy.Explanation:In an isobaric process, pressure $P$ remains constant.If the volume changes from $V_i$ to $V_f$, the work done is:$$W = P\Delta V = P(V_f - V_i)$$So work done is not zero when the volume changes.The first law of thermodynamics gives:$$Q = \Delta U + W$$The heat supplied is used partly to change internal energy and partly to do work.For an ideal gas, internal energy depends on temperature.In an isobaric process, the temperature generally changes, so the change in internal energy $\Delta U$ is not zero.Answer:Option C: change in internal energy is not zero.