//Chapter-1,Example 1_24,Page 1-47 clc() //Given Data: //Dn=2*D40 //Calculations: //As Dn^2=4*n*R*lam/u and Dn^2=4*D40^2 //i.e. 4*n*R*lam/u=4*4*40*R*lam/u .hence, n=4*40 //order of the required ring printf('Order of the dark ring which will have double the diameter of that of 40th ring is =%.0f ',n)