In an optics laboratory, a researcher investigates the propagation of a green laser beam across the boundary from air into a synthetic diamond semi-cylindrical prism. The researcher measures the angle of incidence, θi\theta_iθi, and the corresponding angle of refraction, θr\theta_rθr.
The experimental measurements are recorded in the table below:
| Angle of incidence, θi\theta_iθi (∘^{\circ}∘) | Angle of refraction, θr\theta_rθr (∘^{\circ}∘) |
|---|---|
| 10 | 4.1 |
| 20 | 8.1 |
| 30 | 11.9 |
| 40 | 15.4 |
| 50 | 18.5 |
| 60 | 21.0 |
| 70 | 22.8 |
| 80 | 24.0 |
The data points and the line of best fit are plotted on the graph below:
Describe how the angle of refraction, θr\theta_rθr, changes as the angle of incidence, θi\theta_iθi, increases from 10∘10^{\circ}10∘ to 80∘80^{\circ}80∘.