Which of the following materials refracts RADAR beams?

The refraction of RADAR beams occurs when the beams pass through materials that alter their velocity and direction. Glass is a good example of a material that effectively refracts RADAR beams due to its transparent nature and distinct refractive index compared to air. As RADAR waves enter glass, they slow down and change direction, leading to bending of the beams.

In contrast, materials such as wood, stone, and concrete do not significantly refract RADAR beams. Instead, these materials often reflect or absorb RADAR waves, resulting in limited bending of the waves. The distinct properties of glass—specifically, its ability to transmit and modify the path of RADAR beams—make it the correct choice in this context.