# PROBLEM 5 # 

 Standard formula used 
 theta_c = asin(mu2 / mu1) * (180 / pi). 
 NA = sqrt(mu1^2 - mu2^2). 
 theta_0 = asin(NA) * (180 / pi). 

 Critical angle at the core - cladding boundary is 74.909815 degree 
 Critical angle at cladding - air boundary is 45.584691 degree