clc
//Given
t=40// length of tube in cm
lambda=5e-5// wavelength of incident light in cm 
n=150// order of fringe
//Sample Problem 13 Page No. 52
printf("\n # Problem 13 # \n")
printf(" \n Standard formula used \n   (mu – 1 )*t = n* lambda \n")
t=n*lambda/t+1
printf("\n Refractive index of oil film is %f  .", t)