Question

One mole of gas absorbs 200 J heat at constant volume. Its temperature rises from 298 K to 308 K. The change in internal energy is:

• A. 200 J
• B. -200 J
• C. $200\times \frac{308}{298}$ J
• D. $200\times \frac{298}{308}$ J

Answer 1

The correct option is A 200 J

From the first law of thermodynamics,
$\Delta U=q+w$
Where $\Delta U=\text{internal energy}$
Since volume is constant, hence $w=-P\Delta V=0$
$\therefore \text{internal energy}=\Delta U=q=200J$