The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is\

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Professor PC Thomas Classes · Answer

(c) : Heat energy given $d \mathrm{Q}=d U+d W$ where $d U$ is the change in internal energy and $d W$ is the work done.\ Given $d Q=2 \mathrm{kcal}=2000 	imes 4.2 \mathrm{~J}$ and $d W=500 \mathrm{~J}$\ $	herefore \quad 2000 	imes 4.2=d U+500 \Rightarrow d U=7900 \mathrm{~J}$\