Question

The entropy change for a system is given as:

• A. $\Delta S=\frac{\Delta U}{T}$
• B. $\Delta S=\frac{q}{T}$
• C. $\Delta S=\frac{P\Delta V}{T}$
• D. None of these.

Answer 1

The correct option is B $\Delta S=\frac{q}{T}$

The thermodynamic definition of entropy is based on the expression:
$dS=\frac{q}{T}$
for a measurable change :
$\int dS=\int \frac{d{q}_{rev}}{T}$
$\Delta S=\frac{q}{T}$