A ray of light is moving from air to medium .If the angle of incidence is changing from 45° to 60°,the angle of refraction changes from 30° to .Options here 1)sin inverse of √3÷2√2)2) sin inverse of (√3÷2)3) sin inverse of (2√3÷√2)4) sin inverseof (√3÷2)

Let initial angle of incidence is i,respective angle of refraction is r & final angle of incidence is i',respective angle of refraction is r'

Given that,     i=45 degree,i'=60 degree
                       r=30 degree
                      & r'=?
  Refractive index (n)= sini/sinr 
  since refractive index of a medium is constant 
  So     sini/sinr = sini'/sinr'
    Putting the value of i,i'& r;
    sin45/sin30 = sin60/sinr' 
  Solving it,we get
 r'=sin inverse of root three upon two root two 
that is option (1) is write.