* No refraction: The light ray does not bend. Since it enters perpendicularly, the angle of incidence is 0 degrees. According to Snell's Law (n1 * sin(θ1) = n2 * sin(θ2)), the angle of refraction (θ2) will also be 0 degrees.
* Change in speed: The speed of light changes as it moves from air (or vacuum) to glass. Glass has a higher refractive index than air, meaning light travels slower in glass.
* Partial reflection: Some of the light will be reflected back into the air. This is known as reflection at normal incidence.
In summary: The ray of light passes straight through the glass block without bending, but its speed changes. A small portion of the light is reflected back.
