added graphic

diff --git a/solid_state_physics/tutorial/1_03s.tex b/solid_state_physics/tutorial/1_03s.tex
index dd97aa2..777f575 100644 (file)
--- a/solid_state_physics/tutorial/1_03s.tex
+++ b/solid_state_physics/tutorial/1_03s.tex
@@ -71,7 +71,8 @@
         \item $v_{average}=\frac{1}{t_0}\int_{0}^{t_0} v(t) dt
                          =-\frac{eE}{m}\frac{1}{t_0}[\frac{t^2}{2}]_{0}^{t_0}
                          =-\frac{eE}{m}\frac{t_0}{2}=:-\frac{eE}{m}\tau$,
-              $\qquad t_0=2\tau$
+              $\qquad t_0=2\tau$, $v_{drift}=2v_{average}$
+             \includegraphics[width=12cm]{drude_v.eps}
        \item Each of the $n$ electrons per unit volume
              transfer the kinetic energy $\frac{1}{2}mv^2_{drift}$
              once per $t_0$ to the lattice