diff --git a/src/4_sommerfeld_model_solutions.md b/src/4_sommerfeld_model_solutions.md
index f668d813f738fcc8b9106a9371a26cc0bb43aadb..dd16adf12a050a3cb244ad7d79d9d1489e67444c 100644
--- a/src/4_sommerfeld_model_solutions.md
+++ b/src/4_sommerfeld_model_solutions.md
@@ -198,6 +198,6 @@ $$
 4.
 
 $$
-C_v(T) = \frac{\partial E}{\partial T} = \frac{3Ak_B^2T^2}{\pi c^2}
+C_v(T) = \frac{\partial E}{\partial T} = \frac{3Ak_B^3T^2}{\pi c^2}
 $$