Chapter 12 Self-Quiz

Achievement Chart Categories

  • K/U: Knowledge/Understanding

  • T/I: Thinking/Investigation

  • C: Communication

  • A: Application

Self-Quiz Questions

  • Question Format: Choose the best answer from four alternatives.

Knowledge/Understanding Questions

  1. Refraction of light when transitioning from Air to Water:

    • Answer Options:

      • (a) The light bends toward the normal.

      • (b) The light bends away from the normal.

      • (c) The light continues on a straight path and does not bend.

      • (d) The light is completely reflected off the surface of the water.

    • Concept Reference: 12.1

    • Answer: When light transitions from air to water, it bends toward the normal. This is due to the change in speed of light as it enters a denser medium like water. The correct answer is (a).

  2. Calculating Speed of Light in Glass:

    • Given: Index of refraction for glass is 1.52

    • Options:

      • (a) 1.52 imes 10^{8} ext{ m/s}

      • (b) 1.97 imes 10^{8} ext{ m/s}

      • (c) 3.00 imes 10^{8} ext{ m/s}

      • (d) 6.57 imes 10^{8} ext{ m/s}

    • Concept Reference: 12.4

    • Answer: Given the index of refraction for glass is 1.52, the speed of light in glass can be calculated using the formula v = \frac{c}{n}, where c is the speed of light in vacuum (3.00 \times 10^{8} \text{ m/s}) and n is the index of refraction. Therefore, the speed of light in glass is: v = \frac{3.00 \times 10^{8} \text{ m/s}}{1.52} = 1.97 \times 10^{8} \text{ m/s}, which corresponds to option (b).

  3. Placement of a Net to Retrieve a Seashell Underwater:

    • Options:

      • (a) Place the net directly above the image of the shell in the water.

      • (b) Place the net directly behind the image of the shell in the water.

      • (c) Place the net directly in front of the image of the shell in the water.

      • (d) Place the net directly below the image of the shell in the water.

    • Concept Reference: 12.7

    • Answer: To retrieve a seashell underwater, you should place the net directly above the image of the shell in the water (option (a)). This is because the light bending as it passes from water to air causes the image of the shell to appear at a different location than its actual position.

  4. Conditions for Total Internal Reflection:

    • Options:

      • (a) The light ray must bend toward the normal.

      • (b) The angle of reflection must equal the angle of incidence.

      • (c) The angle of incidence must be greater than the critical angle.

      • (d) Light must be travelling faster in the first medium than in the second.

    • Concept Reference: 12.5

    • Answer: - **Conditions for Total Internal Reflection:**

      - **Options:**

      - (a) The light ray must bend toward the normal.

      - (b) The angle of reflection must equal the angle of incidence.

      - (c) The angle of incidence must be greater than the critical angle.

      - (d) Light must be travelling faster in the first medium than in the second.


      - **Concept Reference:** 12.5

      Answer: The correct condition for total internal reflection is (c) The angle of incidence must be greater than the critical angle.

  5. True/False Statements:

    • Statement 5: Light travels faster in cool air than in warm air.

    • Statement 6: The legs of someone standing in water appear to be longer than they actually are.

    • Statement 7: When light refracts, it changes direction as it travels from one medium into another.

    • Answers: - **Statement 5:** Light travels faster in cool air than in warm air.
      - **Answer:** False. Light travels slower in cooler air than in warmer air due to higher density.

      - **Statement 6:** The legs of someone standing in water appear to be longer than they actually are.
      - **Answer:** True. This is due to the refraction of light, which causes the image to shift.

      - **Statement 7:** When light refracts, it changes direction as it travels from one medium into another.
      - **Answer:** True. Refraction occurs when light passes through different media and changes speed, resulting in a change in direction.

Fill in the Blanks

  1. If the angle of incidence of a light ray passing through water is greater than the critical angle for water, the resulting light ray will reflect back into the water.

    • Concept Reference: 12.5

  2. Triangular prisms are more useful in optical devices than mirrors because these prisms reflect almost 100% of the light internally.

    • Concept Reference: 12.5

  3. The index of refraction for a given medium is a dimensionless quantity because it has no units.

    • Concept Reference: 12.4

Matching Questions

  1. Match each term on the left with the most appropriate description on the right:

    • (a) Index of refraction

      • (iii) The ratio of the speed of light in a vacuum to its speed in a medium

    • (b) Mirage

      • (v) An image that appears to be a puddle of water on the road at a distance

    • (c) Dispersion

      • (i) The result of white light passing through a prism

    • (d) Total Internal Reflection

      • (ii) The process that makes a diamond sparkle

    • (e) Retro-reflector

      • (iv) A device used on road signs to make them visible at night

    • Concept References: 12.4, 12.5, 12.7

Short Answer Questions

  1. Example of Partial Reflection and Refraction: Provide a scenario where light undergoes both processes simultaneously.

    • Concept Reference: 12.1

  2. Explanation of Straight Lines and Bend of Light: Discuss how light travels in straight lines but also bends, and why these concepts do not contradict each other.

    • Concept Reference: 12.1 / T/I

  3. Indices of Refraction from Table 1:

    • Table 1:

      • Medium A: Index of refraction = 2.30

      • Medium B: Index of refraction = 1.76

      • Medium C: Index of refraction = 1.98

    • Analysis:

      • (a) Fastest: Medium B

      • (b) Slowest: Medium A

    • Concept Reference: 12.4

  4. Calculation of Index of Refraction for Sulfuric Acid:

    • Speed Given: 2.11 imes 10^{8} ext{ m/s}

    • Formula: n = rac{c}{v}

    • Where:

      • c = Speed of light in a vacuum: 3.00 imes 10^{8} ext{ m/s}

      • v = Speed of light in sulfuric acid

    • Calculations: Show your work here.

    • Concept Reference: 12.4

  5. Fibre Optics Technology:

    • (a) Explanation of how light is utilized in fibre optics technology.

    • (b) Importance of having a small critical angle in materials for producing fibre optic cables.

    • Concept Reference: 12.5

  6. Uses for Retro-reflectors in Home: Suggest at least two practical applications for retro-reflectors in home settings.

    • Concept Reference: 12.5

  7. Interpretation of Information by Eyes and Brain: Compare how images are interpreted in a plane mirror versus an underwater image.

    • Concept References: 12.7, 11.7 / T/I

  8. Dispersion of White Light:

    • (a) Discuss why colours exit a prism in a specific order when white light passes through.

    • (b) Explanation of whether red laser light would disperse through a prism and why or why not.

    • Concept References: 12.7, 11.3 / T/I

  9. Visibility of Rainbow During Rainstorm: Analyze the possibility of seeing a rainbow with clouds between you and the sun.

    • Concept Reference: 12.7 / T/I

  10. Devices Utilizing Total Internal Reflection:

    • (a) Name three devices that utilize total internal reflection.

    • (b) Illustrate total internal reflection with a diagram, including light direction and critical angle.

    • Concept Reference: 12.5

  11. Definition of Apparent Depth: Write a definition in your own words.

    • Concept Reference: 12.7

  12. Reality of Mirages: Discuss your friend’s claim about mirages not existing and whether their claim holds validity.

    • Concept Reference: 12.7 / T/I

  13. Ad Design for Special Coating on Car Windows: Create an advertisement illustrating how a special coating works that allows vision out while limiting visibility in.

    • Concept Reference: 12.6 / C