If there is no disturbance in a medium, such as an absence of particles or any changes in the properties of the medium, light would propagate through it without any interactions or deviations. In this scenario, light would continue to travel in a straight line at a constant velocity, which is the speed of light in that particular medium.
When light encounters a medium, it interacts with the particles or atoms present in that medium. These interactions can lead to phenomena such as absorption, scattering, or refraction, depending on the properties of the medium and the characteristics of the light.
However, if there are no disturbances or interactions occurring within the medium, light would pass through it unaffected, as there would be no obstacles or changes in the medium's properties to cause any deviations or alterations to the light's trajectory.