The factor

What is the factor that determines whether an object will be transparent, translucent, or opaque?
Also, what makes reflecting surfaces reflect EM rays?


Gold Member
Both factors are based upon how the atomic structure of the material interacts with photons of various energy levels (frequencies). Photons are absorbed by atoms, then new ones radiated in some specific direction. Reflection entails the re-radiated particles coming out the same side of the atom that the originals entered. The real scientists around here can provide clarification and even formulae, but it's a start.

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving