a bunch fo phys

content/physics/thermodynamics.md

@@ -25,7 +25,7 @@ When it comes to energy transfer and phase changes there are only two useful equ
 
 These equations together describe the heat energy required for changing the temperature of a substance and for changing its phase.
 
-**It is important to note the alternate arrangement of both:
+**It is important to note the alternate arrangement of both**:
 $$
 Q=nc_{\mathrm{mol}}\Delta T = \Delta \textbf{KE}
 $$
@@ -91,3 +91,16 @@ P_b=A\varepsilon \sigma\cdot T^4
 $$
 Where $A$ is the area of the exposed surface.
 
+## Emissivity and Albedo 
+
+Emissivity $\varepsilon$ is given by :
+$$
+\varepsilon=\frac{P_{\text{obj}}}{P_b}
+$$
+Albedo is given by:
+$$
+\alpha=\frac{P_\text{reflected}{P_{\text{incoming}}}}
+
+This is where the Boltzmann law comes in to play. In order to calculate the emissivity of an object, you first need bot: the power of emissions from the target object, and the Power that would be emitted by a black body of the same temperature. This value can be procured using the Stefan Boltzmann Law of Radiation. 
+
+Albedo, however, is a far simpler quantity, relying only on the input and output energies of the object.