Question 21: Thermodynamics & KTG

Question

In a certain process, 400 cal of heat is supplied to a system and at the same time 105 J of mechanical work was done on the system. The increase in its internal energy is

Accepted Answer

$$ \begin{aligned} &	ext { }\ &\begin{aligned}Here, \,\, d Q & =400 \mathrm{cal}, d W=-105 \mathrm{~J} \ & =-\frac{105}{4.2} \mathrm{cal}=-25 \mathrm{cal} ; d U=? \end{aligned} \end{aligned} $$
Now, $d U=d Q-d W$
$$ d U=400-(-25)=425 \mathrm{cal} $$
Note $d W$ is negative because work is done on the system.

Answer

20 cal

Answer

303 cal

Answer

404 cal

Answer

425 cal

Thermodynamics & KTG

In a certain process, 400 cal of heat is supplied to a system and at the same time 105 J of mechanical work was done on the system. The increase in its internal energy is

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