Question

A system is provided with $95.2cal$ of heat and the work done by the system on the surrounding is $40J$. The internal energy

• A. Increases by $600J$
• B. Increases by $760J$
• C. Increases by $560J$
• D. None of these

Answer 1

The correct option is D None of these

From first law of thermodynamic, $△U=q+W$
$q=95.2cal=95.2\times 4.2J=400J$
$W=-40J$ (as work is done by the system)
putting the values,
$△U=q+w=400-40=360J$

So internal energy increases by $360J$