room is totally dark. light source is ultraviolet. beam of light does not travel toward the students. room walls are shielded with insulating material.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: While conducting an investigation on refraction, a teacher uses a red laser pointer to show how a beam of light is affected as it passes through several glass objects. The teacher should make sure that the
Possibilities:
- room is totally dark.
- light source is ultraviolet.
- beam of light does not travel toward the students.
- room walls are shielded with insulating material.

beam of light does not travel toward the students.