Class 8 Science Ch. 13 Light

Class 8 Science Ch. 13 Light

1. Why does light reflect from all surfaces?

• Light reflects from all surfaces due to the phenomenon of reflection.

1. Under what conditions does regular reflection occur?

• Regular reflection occurs when light is incident on smooth, polished, and regular surfaces.

1. What distinguishes diffused or irregular reflection from regular reflection?

• Diffused or irregular reflection takes place from rough surfaces.

1. State the two laws of reflection.

• The two laws of reflection are: (i) The angle of incidence is equal to the angle of reflection. (ii) Incident ray, reflected ray, and the normal drawn at the point of incidence to the reflecting surface lie in the same plane.

1. What change does an image undergo in a plane mirror?

• An image formed in a plane mirror undergoes lateral inversion.

1. How do two mirrors inclined to each other produce multiple images?

• Two mirrors inclined to each other give multiple images.

1. What causes the formation of beautiful patterns in a kaleidoscope?

• Beautiful patterns are formed in a kaleidoscope because of multiple reflections.

1. How is sunlight, also called white light, composed?

• Sunlight, called white light, consists of seven colors.

1. What is the process known as when light is split into its constituent colors?

• Splitting of light into its constituent colors is known as dispersion.

1. List the parts of the eye.
   • The parts of the eye are cornea, iris, pupil, lens, retina, and optic nerve.
2. What allows a normal eye to see nearby and distant objects clearly?
   • A normal eye can see nearby and distant objects clearly.
3. How do visually impaired persons read and write using the Braille system?
   • Visually impaired persons can read and write using the Braille system.
4. What happens to the other senses of visually impaired persons to improve their interaction with the environment?
   • Visually impaired persons develop their other senses more sharply to improve their interaction with their environment.
5. Why is regular reflection more likely to occur on smooth, polished surfaces?
   • Regular reflection is more likely to occur on smooth, polished surfaces due to the nature of the surface.
6. Explain the concept of lateral inversion in the context of an image formed in a plane mirror.
   • Lateral inversion refers to the left-right reversal of an image formed in a plane mirror.
7. How do two mirrors inclined to each other create multiple reflections, and what is this phenomenon called?
   • Two mirrors inclined to each other create multiple reflections, a phenomenon known as multiple images.
8. What is the significance of the two laws of reflection in understanding the behavior of light?
   • The two laws of reflection provide rules governing the behavior of light when it interacts with surfaces, aiding our understanding of its behavior.
9. How does dispersion occur, and what is its effect on white light?
   • Dispersion occurs when light is split into its constituent colors, and its effect on white light is the separation of colors into a spectrum.
10. Enumerate the parts of the eye and briefly describe their functions.
    • The eye comprises the cornea, iris, pupil, lens, retina, and optic nerve, each with a specific function in the process of vision.
11. How does the Braille system enable visually impaired individuals to read and write?
    • The Braille system uses raised dots to represent letters and characters, allowing visually impaired individuals to read and write through touch.
12. Why do visually impaired persons often develop their other senses more sharply?
    • Visually impaired persons develop their other senses more sharply as a compensation mechanism for their impaired vision, enhancing their interaction with the environment.
13. Describe the role of the cornea, iris, pupil, lens, retina, and optic nerve in the process of vision.
    • The cornea, iris, pupil, lens, retina, and optic nerve play distinct roles in the process of vision, contributing to the formation and transmission of visual signals to the brain.
14. Explain the term “white light” and its composition in sunlight.
    • “White light” in sunlight is composed of seven colors, as revealed through the process of dispersion.
15. How does the ability of a normal eye to see both nearby and distant objects contribute to its functionality?
    • The ability of a normal eye to see both nearby and distant objects contributes to its versatility and functionality in various visual tasks.
16. What is the scientific explanation for the formation of patterns in a kaleidoscope based on multiple reflections?
    • The formation of patterns in a kaleidoscope is scientifically explained by the phenomenon of multiple reflections, creating intricate and symmetrical designs.
17. How do the laws of reflection help us understand the behavior of light when it interacts with surfaces?
    • The laws of reflection provide a framework to understand how light behaves upon interacting with surfaces, guiding its direction and behavior.
18. In what ways does the dispersion of light play a role in natural phenomena or everyday experiences?
    • The dispersion of light contributes to various natural phenomena, such as the formation of rainbows, and impacts everyday experiences involving the separation of light into its component colors.
19. Discuss the importance of developing enhanced senses in visually impaired individuals for better interaction with their surroundings.
    • Developing enhanced senses in visually impaired individuals is crucial for improving their interaction with the surroundings, compensating for their impaired vision and fostering independence.
20. Can you explain the process of multiple reflections in a kaleidoscope and how it contributes to the creation of intricate patterns?
    • Multiple reflections in a kaleidoscope result from light bouncing off multiple surfaces, creating intricate patterns through the repeated and symmetrical arrangement of reflected images.
21. How does the presence of rough surfaces influence the phenomenon of diffused or irregular reflection compared to smooth surfaces?
    • Rough surfaces influence diffused or irregular reflection more than smooth surfaces, causing light to scatter in different directions due to the uneven nature of the surface.