Refraction & Total Internal Reflection Quiz
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5 questions, one answer each
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1. What happens to light as it passes from air into glass?
- A. It speeds up and bends away from the normal
- B. It slows down and bends towards the normal
- C. It slows down and bends away from the normal
- D. Its speed and direction stay the same
2. Which equation correctly states Snell's Law?
- A. n = sin r / sin i
- B. n = 1 / sin c
- C. n = sin i / sin r
- D. n = speed in medium / speed in vacuum
3. Total internal reflection occurs when...
- A. light travels through a vacuum
- B. the angle of incidence in the denser medium is less than the critical angle
- C. the angle of incidence in the denser medium exceeds the critical angle
- D. light hits the boundary along the normal
4. A material has a critical angle of 42°. Which equation gives its refractive index?
- A. n = 1 / sin 42°
- B. n = sin 42°
- C. n = 42 / sin 1°
- D. n = sin 42° / 1
5. Why can optical fibres carry light signals around bends without significant loss?
- A. The light travels slower than sound in the fibre
- B. The fibre material absorbs and re-emits the light at each bend
- C. Light undergoes repeated total internal reflection off the fibre walls
- D. The fibre acts as a lens that refocuses the light at each bend