//Example 2_2_u2
clc();
clear;
//To corresponding mean free path and compare with experimental value
row=6.87*10^7                  //units in Kg/m^3
m=9.11*10^-31               //units in Kgs
n=5.86*10^28                         //units in m^-3
e=1.6*10^-19                     //units in  coulombs
t=(row*m)/(n*e^2)         //units in s
printf("The mean free path is t=")
disp(t)
printf("sec")
kb=1.381*10^-23           //units in m^2 kg s^-2 K^-1
T=300                   //units in K
m=9.11*10^-31                          //units in Kgs
v=(sqrt(3*kb*T))/sqrt(m)         //units in m/s
printf("\nVelocity v=%.2f m/s\n",v)
lamda=t*v //units in meters
printf("Wavelength is lamda=")
disp(lamda)
printf("meters")
printf("\nThe experimental value is ten times higher than predicted value")
//In textbook the answer is printed wrong as t=2.84*10^-14 s and lamda=3.28*10^-9 meters but correct answer is t=4.172D-14sec and lamda=4.873D-09 meters