light bends as it enters a glass block. which type of wave behaviour is this?

The wave behaviour is refraction.

Quick Scoop

When light passes from air into a glass block, it changes speed because glass is denser and has a different refractive index from air. This change in speed makes the light ray change direction at the boundary, which is exactly what is meant by refraction.

In school physics questions written exactly like this one, “Light bends as it enters a glass block. Which type of wave behaviour is this?” the expected one- word answer is refraction.

So if you’re filling in a blank or answering a quiz, just write: refraction.

TL;DR: Light bends entering glass because its speed changes in a new medium; this wave behaviour is called refraction.

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