Thermodynamics and Thermochemistry - Result Question 4
4. During compression of a spring the work done is $10$ $ kJ$ and $2$ $kJ$ escaped to the surroundings as heat. The change in internal energy, $\Delta U$ (in $kJ$ ) is
(2019 Main, 9 April II)
(a) $8$
(b) $-12$
(c) $12$
(d) $-8$
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Answer:
Correct Answer: 4. (a)
Solution:
In the given system, during the compression of a spring the workdone is $10 $ $kJ$ and $2$ $ kJ$ of heat is escaped to the surroundings. So, $q=-2$ $ kJ$ and $W=10 $ $kJ$
According to the first law of thermodynamics,
$\begin{aligned} & \Delta U=q+W=-2 kJ+10 kJ \\ & \Delta U=8 kJ \end{aligned}$
The change in internal energy, $\Delta U$ (in $kJ$ ) is $8 $ $kJ$.
BETA
