Q. A liquid when kept inside a thermally insulated closed vessel at $25^\circ$C was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters ?
A) $\Delta U<0,\ q=0,\ w>0$
B) $\Delta U=0,\ q=0,\ w=0$
C) $\Delta U>0,\ q=0,\ w>0$
D) $\Delta U=0,\ q<0,\ w>0$
Explanation
[Solution by Dr. Abubacker] The vessel is thermally insulated, so $q=0$. Stirring does work on the liquid ($w>0$), so $\Delta U=q+w>0$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.