clc 
// Given that
d = 12e-6 // diameter in m
d_ = 90e-9 // diameter of nanoparticle in m
// Sample Problem 1 on page no. 22.13
printf("\n # PROBLEM 1 # \n")
r = d / 2
r_ = d_ / 2
k = r / 3
k_ = r_ / 3
R = k_ / k
printf("\n The ratio of the value of Nb/Ns of spherical particle and nanoparticle = %e .",R)