Question

If $\Delta U$ and $\Delta W$ represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

• A. $\Delta U =- \, \Delta W, $ in a adiabatic process
• B. $\Delta U =\, \Delta W, $ in a isothermal process
• C. $\Delta U =\, \Delta W, $ in a adiabatic process
• D. $\Delta U =\, -\Delta W, $ in a isothermal process

Answer 1

Answer: (A)

$\Delta U=q+W$
for an adiabatic process, $q=0$
$\therefore \Delta U = W$
i.e; increase or decrease in Internal energy is equal to work done.