Question

The work done by a system is $8$ joule, when $40$ joule is supplied to it. What is the increase in internal energy of system.

Answer 1

$dQ=40Jdw=-8J$

$dQ=du+dw$

$du=dQ-dw=40-(-8)=48J$

Therefore there is a increase in internal energy of a system by $8J$

$\therefore du=48J$