// Exa 2.29
clc;
clear;
close;
// Given data
N_D= 1.4*10^24;// per m^3
ni= 1.4*10^18;// per m^3
n=N_D;//per m^3
p=ni^2/n;// per m^3
R= n/p;// ratio of electron to holes concentration
disp(R,"Ratio of electron to holes concentraiton is : ")