Answer:
65.48°
Step-by-step explanation:
Using Snell's law as:
Where,
is the angle of incidence (? )
is the angle of refraction ( 30.0° )
is the refractive index of the refraction medium (diamond, n=2.42)
is the refractive index of the incidence medium (water, n=1.33)
Hence,
Angle of incidence =
= 65.48°