Question

A gas present in a cylinder fitted with a frictionless piston expands against a constant pressure of $1$ atm from a volume of $2$ litre to a volume of $6$ litre. In doing so, it absorbs $800$ J heat from surroundings. Determine increase in internal energy of process.

Answer 1

Solution:- $804J$

Given:-

$q=800J$

$P=1atm$

$V_1=2L$

$V_2=6L$

$\Rightarrow \Delta V=(V_2-V_1)=6-2=4L$

$\therefore W=P.\Delta V=1\times 4=4J$

$\therefore \text{Increase in internal energy of process}\left(\Delta U\right)=q+W=800+4=804J$