Technical Sciences Grade 12 · Term 2 · 9 questions
Light Reflection, refraction, and Total Internal Reflection (critical angle) Questions and Answers Grade 12
9 exam questions on this topic from Technical Sciences Grade 12 past papers, each with a full answer.
What the ATP covers
Week 7: Light Reflection, refraction, and Total Internal Reflection (critical angle). Dispersion and the use of lenses (convex/concave).
Exam Questions
Hide answers Expand allC: Diagram C
A concave lens is a diverging lens: parallel rays spread out after passing through it (diagram C).
B: refraction away from the normal.
The angle of incidence is smaller than the critical angle, so there is no total internal reflection. Light moving from a denser to a less dense medium bends away from the normal.
Refraction is the bending of light when it passes from one medium into another.
Behind the object, on the same side of the lens as the object (between the lens and F).
The three characteristics of the image are:
- It is virtual, so it cannot be projected on a screen.
- It is upright, with the same orientation as the object.
- It is magnified, so it is larger than the object.
Two applications of a convex lens are:
- A telescope.
- Binoculars (a magnifying glass or a camera lens is also correct).
The object sits exactly at the focal point, so the rays leave the lens parallel to each other. Parallel rays never meet, so no real image forms.