Question

The entropy change when 400 J of heat is absorbed reversibly at 400 K is:

• A. 0.5 J K$^{-1}$
• B. 1 J K$^{-1}$
• C. 2 J K$^{-1}$
• D. 4 J K$^{-1}$

Hint:

Ensure that the temperature is always in Kelvin (K) when calculating thermodynamic properties like entropy change.
If the temperature is given in Celsius, add 273.15 to convert it to Kelvin.
Pay attention to the sign: absorption of heat increases entropy ($+q$), while release of heat decreases entropy ($-q$).

Answer 1

The Correct Option is B

Step 1: Entropy change.
$\Delta S = Q_{rev}/T = 400/400$
\[ \boxed{\Delta S = 1 \text{ J/K}} \]