Refraction Quiz - CBSE Class 9 Science

Free practice quiz: Refraction (CBSE Class 9 Science). 20 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 9 Science practice quiz has 20 multiple-choice questions on Refraction, and 20 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. What is refraction?

   1. The bending of light when it passes through a medium
   2. The bouncing of light off a surface
   3. The scattering of light by small particles
   4. The absorption of light by a medium
   Show answer

   Answer: A. The bending of light when it passes through a medium

   Refraction is defined as the bending of light as it passes from one medium to another with a different refractive index.

2. Which of the following materials has the highest refractive index?

   1. Diamond
   2. Water
   3. Air
   4. Glass
   Show answer

   Answer: A. Diamond

   Diamond has the highest refractive index among the options given, causing light to slow down significantly and bend.

3. What is total internal reflection?

   1. The phenomenon when light reflects completely within a medium
   2. The bending of light away from normal at low angles
   3. Reflection that occurs on a rough surface
   4. Inclination of light rays after refraction
   Show answer

   Answer: A. The phenomenon when light reflects completely within a medium

   Total internal reflection is when the light is completely reflected at the boundary of two media due to a large angle of incidence beyond the critical angle.

4. What happens in an optical fiber due to refraction?

   1. Multiple total internal reflections
   2. Light is absorbed completely
   3. Immediate refraction out of fiber
   4. Constant refraction along fiber
   Show answer

   Answer: A. Multiple total internal reflections

   Optical fibers use refraction to guide light through the core, undergoing successive total internal reflections due to the high refractive index difference with cladding.

5. What is the importance of refractive index in optical coherence tomography (OCT)?

   1. Determines resolution by light scattering
   2. Is crucial for gathering magnetic fields
   3. Has no relevance to OCT
   4. Dictates the path of electrical signals
   Show answer

   Answer: A. Determines resolution by light scattering

   In OCT, refractive index variance affects light scattering properties, thereby influencing image resolution and depth accuracy during non-invasive diagnostic imaging.

More questions in this quiz

Answers and explanations are in the full quiz.

1. When does light not refract?
2. How does the refractive index affect the speed of light in a medium?
3. If a ray of light passes from air (n=1) to water (n=1.33), how does it bend?
4. What causes refraction?
5. Which law relates the angles of incidence and refraction to the refractive indices of two media?
6. What happens to light waves when they pass from air into water?
7. What is the critical angle for water (n=1.33) to air (n=1)?
8. Why does a straw appear bent when placed in a glass of water?
9. How do lenses use refraction to magnify objects?
10. A convex lens forms an image at a distance twice the focal length. What is the nature of the image?
11. How is refraction demonstrated in a prism?
12. Which of the following factors does NOT affect the degree of refraction?
13. Why is knowledge of refraction important for designing corrective lenses?
14. How does atmospheric refraction affect sunrise and sunset?
15. Explain the concept of negative refractive index.

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