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Chapter Analysis
Intermediate17 pages • EnglishQuick Summary
The chapter 'Light' for Class 8 Science deals with the behavior of light, including reflection and refraction. It explains laws of reflection, and differentiates between regular and diffused reflection. The chapter also discusses how light enables us to see objects, the formation of images using mirrors, and includes a brief overview of human vision and optical instruments.
Key Topics
- •Reflection of light
- •Laws of reflection
- •Regular and diffused reflection
- •Image formation
- •Human eye structure
- •Kaleidoscope
- •Dispersion of light
- •Care of the eyes
Learning Objectives
- ✓Understand the basic properties of light and its behavior.
- ✓Learn the laws of reflection and how they are applied.
- ✓Differentiate between types of reflection.
- ✓Comprehend image formation by plane mirrors.
- ✓Identify the parts and functions of the human eye.
- ✓Explore optical instruments like the kaleidoscope.
Questions in Chapter
1. Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room? Explain.
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2. Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?
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3. Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each case.
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4. State the laws of reflection.
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5. Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence lie in the same plane.
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6. Fill in the blanks in the following.
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7. Angle of incidence is equal to the angle of reflection.
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8. Image formed by a plane mirror is
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9. Describe the construction of a kaleidoscope.
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10. Draw a labelled sketch of the human eye.
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Additional Practice Questions
Explain how a periscope works.
mediumAnswer: A periscope works using two plane mirrors set parallel to each other at an angle of 45 degrees, allowing one to see objects above or around obstacles.
What causes dispersion of light?
mediumAnswer: Dispersion occurs when white light is separated into its constituent colors by passing through a medium like a prism, which splits the light due to refraction.
How does the human eye adjust to focus at different distances?
mediumAnswer: The human eye adjusts focus using the ciliary muscles that change the shape of the lens to focus light onto the retina, enabling clear vision at various distances.
Differentiate between luminous and illuminated objects.
easyAnswer: Luminous objects emit their own light, such as the sun, while illuminated objects reflect light from other sources.
Why is regular reflection important for image formation?
easyAnswer: Regular reflection is important because it reflects light in a uniform direction, allowing clear images to be formed.
NCERT Exemplar
AvailablePractice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.
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