// Exa 3.21.20
clc;
clear;
close;
// Given data
n_i = 1.5 * 10^16;// in /m^3
n_n = 5 * 10^20;// in /m^3
p_n = (n_i)^2/n_n;// in /m^3
disp(p_n,"The majority carrier density per m^3 is");