Question

what is the angle of refraction when the angle of incidence is 30 degree 45 degree and 60 degree

Answer 1

Angle of refraction is dependent upon the refractive index of the 1st and 2nd medium.
Sin i
$sin \: i \div sin \:r = refractive \: index \: of \: second \: medium \div refractive \: index \: of \: second \: medium$