Question

If an insulated container containing liquid is stirred with a paddle to increase the temepraturr which of the following is true?

• A. $\Delta U=W\ne 0,q=0$
• B. $\Delta U=W=0,q\ne 0$
• C. $\Delta U=0,W=0,q\ne 0$
• D. $W=0,\Delta U=q\ne 0$

Answer 1

The correct option is A $\Delta U=W\ne 0,q=0$

As it is an insulated container containing liquid, heat is neither absorbed nor released$⟹$ q=0

But stirring with a paddle does some work and this increases the temperature,

$\therefore$ an increase in internal energy exists

$\therefore W\ne 0$ , $△U\ne 0$