Mission RL6: TIR and Critical Angle

Mission RL6 pertains to the concept of a critical angle and the relationship between the critical angle and the tendency of a light ray with a stated angle of incidence to undergo total internal reflection. The mission consists of 38 questions organized into 10 Question Groups. You must answer one question from each Question Group to complete the mission. The learning outcomes for this mission are ...

Learning Outcomes

  • The student should be able to define critical angle and use the concept to determine whether a light ray would undergo total internal reflection in any given situation.
  • The student should be able to combine a conceptual and mathematical understanding of critical angle in order to compare critical angles for different boundaries if given a diagram or index of refraction values.


Launch Mission RL6


Getting Help

If you are not familiar with this topic, then you should first learn about the topic using our written Tutorial or our Video Tutorial:

The Physics Classroom, Refraction and Lenses Unit, Lesson 3, Part b

The Physics Classroom, Refraction and Lenses Unit, Lesson 3, Part c


Video Tutorials:

Total Internal Reflection

The Critical Angle



Question-Specific Help

Each Question Group has its own Help page with information specific to the question. You can access the Help page from within the mission by tapping on the Help Me! icon (textbook). For your convenience, links to those pages are provided below: