• # question_answer A system is provided with 200 cal of heat and the work done by the system on the surrounding is 40 J. Then its internal energy                        A) Increases by 600 J B) Decreases by 800 J C) Increases by 800 J D) Decreases by 50 J

 [c] $\Delta Q=\Delta U+\Delta W$ $\because$$\Delta Q=200cal=200\times 4.2=840J$and $\Delta W=40J$ Þ$\Delta U=\Delta Q-\Delta W=840-40=800J$