clc
//Given
lambda=5.9e-5// wavelength of incident light in cm 
n=10// order of ring 
//Sample Problem 18b Page No. 54
printf("\n # Problem 18b # \n")
printf(" \n Standard formula used \n   2t = n*lambda \n")
t=n*lambda/200
printf(" Thickness of air film is %e m.\n ",t)