Class 6 Science Chapter 8 Important Question Answers - Light, Shadow and Reflections

Very Short Answer Type Questions

Q1: What is a luminous object?
Ans: A luminous object is an object that emits light on its own.

Q2: Give an example of a non-luminous object.
Ans: The moon is an example of a non-luminous object.

Q3: Define transparent medium.
Ans: A transparent medium is a material that allows all the light incident on it to pass through it.

Q4: What is the primary factor affecting the size of a shadow?
Ans: The primary factor affecting the size of a shadow is the distance between the object and the screen.

Q5: What is the principle on which a pinhole camera works?
Ans: The principle on which a pinhole camera works is the principle of straight-line propagation of light.

Q6: What is the shape of the shadow when the source of light is moved closer to the object?
Ans: When the source of light is moved closer to the object, the shadow becomes larger.

Q7: What is a two-way mirror used for?
Ans: A two-way mirror is used for observing people without them knowing they are being watched.

Q8: What type of surface reflects the entire incident light on it?
Ans: A smooth plane surface, like a plane mirror, reflects the entire incident light on it.

Q9: Why is the image in a mirror called a reflection?
Ans: The image in a mirror is called a reflection because it is formed by light bouncing back from the mirror.

Q10: How does the size of an image in a plane mirror compare to the size of the object?
Ans: The size of an image in a plane mirror is the same as the size of the object.

Short Answer Type Questions

Q11: Explain the difference between transparent, translucent, and opaque objects.
Ans: Transparent objects allow all light to pass through, translucent objects allow only some light to pass through and scatter it, while opaque objects do not allow any light to pass through.

Q12: Describe how the size of a shadow changes with variations in the distance between the object and the screen.
Ans: When the distance between the object and the screen is increased, the size of the shadow decreases, and when the distance is decreased, the size of the shadow increases.

Q13: What is a pinhole camera, and how does it create images?
Ans: A pinhole camera is a simple camera that uses a small hole to project an inverted and smaller image of an object onto a surface. It works based on the principle that light travels in straight lines.

Q14: Explain how a two-way mirror works and where it is commonly used.
Ans: A two-way mirror is a glass that acts as a mirror on one side and plain glass on the other. It is used to observe people without their knowledge, commonly used in police investigations or psychological institutions.

Q15: Why is the image in a plane mirror always the same size as the object?
Ans: The image in a plane mirror is the same size as the object because the mirror reflects light in a way that preserves the size and shape of the object.

Long Answer Type Questions

Q16: Discuss the characteristics of transparent, translucent, and opaque objects with examples.
Ans: Transparent objects allow all light to pass through (e.g., glass), translucent objects allow some light to pass through but scatter it (e.g., frosted glass), and opaque objects do not allow any light to pass through (e.g., wood).

Q17: Explain the formation of shadows, and how their size and shape change with variations in light source distance and object orientation.
Ans: Shadows are formed when an opaque object blocks the path of light. The size and shape of shadows change with the distance between the light source and object and with the orientation of the object.

Q18: Describe the construction and working principle of a pinhole camera, and provide an example of its application.
Ans: A pinhole camera is constructed with a small hole and a surface to capture the inverted and smaller image of an object. It works based on the principle of light traveling in straight lines. An application is viewing eclipses.

Q19: Explain the concept of reflection of light and how mirrors produce images. Compare and contrast images in a plane mirror with shadows.
Ans: Reflection of light occurs when light bounces back from a smooth surface like a mirror. Mirrors change the direction of light to form images. Images in a plane mirror are the same size as objects and colorful, while shadows are black and change in size with light source position.

Q20: Discuss the historical development of mirrors, including early methods of mirror-making and their significance.
Ans: Early mirrors were made from polished stones or obsidian. They were significant for personal grooming and early scientific observations. The use of mirrors evolved over time to include modern mirrors used today.