If you walk at a constant pace across a room of known length, ...

[ericka1]

If you walk at a constant pace across a room of known length, your walking speed is the room length divided by the time to cross the room.
 
  Now suppose you repeat your walk but briefly stop along the way to interact with people sitting along your path. What effect does this have on your average speed across the room? How is this analogous to light passing through glass? In what way is it not analogous?
  What will be an ideal response?

Question 2

On a TV screen, red, green, and blue spots of light produce a full spectrum of colors. What spots are activated to produce yellow? Red? Magenta? White?
 
  What will be an ideal response?

[Moriaki]

Answer to Question 1

Answer: When you walk across the room and pause to greet people along the way, you are like light passing through glass, pausing along the way to interact with atoms. Your average speed across the room is lower when interactions occur, much like the speed of light is less in glass than in a vacuum. How this is different is that in the case of walking across the room, you begin the walk and you end it. There is only one you. But in the case of light through glass, the photon that first interacts with the glass is not the photon that emerges through the glass. There is a chain of different but identical photons cascading through the glass.

Answer to Question 2

Answer: Yellow is produced by simultaneously activating red and green; red is activated by red only; magenta by red and blue, and white by equal brightnesses of all three of these colors.

[ericka1]

Thank you!

[Moriaki]

Always glad to help...