Answer:
The angle of incidence is 38.8°.
Step-by-step explanation:
let n1 = 1.5 be the refractive index of glass and ∅1 be the angle of incidence, let n2 be the refractive index of air and ∅2 be the angle of refraction.
by Snell's law:
n1×sin(∅1) = n2×sin(∅2)
sin(∅1) = n2×sin(∅2)/n1
= (1)×sin(70)/1.5
∅1 = 38.8°
Therefore, the angle of incidence is 38.8°.