The speed of light in water, glass and diamond is in the following order

The speed of light in water, glass, and diamond is in the following order: diamond > glass > water, which corresponds to option [A]. Light travels fastest in diamond among these substances due to its highly ordered crystalline structure, which minimizes interactions that slow down light. Glass, while also a transparent material, has a slightly lower speed of light compared to diamond due to its amorphous structure and higher density of atoms compared to diamond. Water, being a liquid with a less ordered molecular arrangement and higher density than glass, further slows down the speed of light compared to both diamond and glass. This order reflects the influence of molecular density, atomic arrangement, and interactions on the propagation of light through different mediums. Understanding these variations is crucial for applications in optics, materials science, and telecommunications, where the speed of light in various substances dictates their suitability for different technological and scientific purposes.