Final answer:
Plexiglass is likely the material that transmitted the most light in the light lab because it is designed to be transparent, unlike the shiny foil, mirror, and one-way mirror, which are reflective surfaces.
Step-by-step explanation:
In considering which material in your light lab transmitted the most light, we need to understand the properties of each material provided in the options. Reflection plays a crucial role here as it affects how much light passes through (or is transmitted by) a material.
A shiny side of the foil and a mirror are highly reflective, which means they redirect most of the light that falls on them. In the case of the mirror, as mentioned, a good-quality one can reflect more than 90% of incident light. However, these reflective surfaces are not about transmitting light, but rather redirecting it.
Plexiglass, on the other hand, allows light to pass through but does not redirect it perfectly because it is not as smooth as a mirror. Finally, a one-way mirror transmits some light and reflects some light, depending on which side you are on. Considering all options, plexiglass likely transmitted the most light since it is designed to be transparent, while the other materials are designed to reflect light.