Thermodynamics Question 3
Question 3 - 2024 (27 Jan Shift 1)
$0.08 kg$ air is heated at constant volume through $5^{\circ} C$. The specific heat of air at constant volume is
$0.17 kcal / kg^{\circ} C$ and $J=4.18$ joule $/ cal$. The change in its internal energy is approximately.
(1) $318 J$
(2) $298 J$
(3) $284 J$
(4) $142 J$
Show Answer
Answer: (3)
Solution:
$Q=\Delta U$ as work done is zero [constant volume]
$\Delta U=ms \Delta T$
$=0.08 \times(170 \times 4.18) \times 5$
$\simeq 284 J$
