Search any question & find its solution
Question:
Answered & Verified by Expert
A gas does $4.5 \mathrm{~J}$ of external work during adiabatic expansion. If its temperature falls by $2 \mathrm{~K}$, then its internal energy will be
Options:
Solution:
2350 Upvotes
Verified Answer
The correct answer is:
decreased by $4.5 \mathrm{~J}$
From first law of thermodynamics,
$\begin{aligned}
& d Q=d U+d W \\
& \Rightarrow \quad d U=-d W \quad \text { [In adiabatic process } d Q=0 \text { ] } \\
& d U=-4.5 \mathrm{~J}
\end{aligned}$
As, the temperature falls so internal energy will decrease by $4.5 \mathrm{~J}$
$\begin{aligned}
& d Q=d U+d W \\
& \Rightarrow \quad d U=-d W \quad \text { [In adiabatic process } d Q=0 \text { ] } \\
& d U=-4.5 \mathrm{~J}
\end{aligned}$
As, the temperature falls so internal energy will decrease by $4.5 \mathrm{~J}$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.