Question

a ray of yellow light crosses the boundary between glass and air, going from glass to air. If the angle of incidence is 30 degrees, what is the angle of refraction

Answer 1

Note that from Snell's law,          
          
n1sin(t1) = n2sin(t2)          
          
where          
          
n1 = index of refraction of first medium =    1.5      
t1 = angle of incidence =    30   degrees  
n2 = index of refraction of second medium =    1      
t2 = angle of refraction
          
Thus,          
          
t2 =    48.59    degrees   [ANSWER]

I used the index of refraction of glass as 1.50. In case you use a different value, please use that one.