Light, Shadows and Reflections – Class 6 Science Notes & Questions Answers (NCERT)
This all-in-one study post for Class 6 Science: Light, Shadows and Reflections combines easy notes and a complete practice set of questions and answers. Use the quick buttons above to jump to the section you need. The notes are concise and concept-focused, and the Q&A section includes 7 MCQs, 7 Very Short, 7 Short, and 7 Long Answer questions to match your exam preparation needs.
📘 Notes – Light, Shadows and Reflections (Class 6)
1) What is Light?
Light helps us see objects. When light from a source reaches our eyes after reflecting from an object, we see that object. Common sources include the Sun, lamps, candles, and LEDs. Objects that give out their own light are called luminous (Sun, flame), while those that do not are non-luminous (book, chair). Non-luminous objects are visible because they reflect light from other sources.
2) Transparent, Translucent, and Opaque
Based on how much light passes through, materials are:
- Transparent: Allow most light to pass through (clear glass, clean water).
- Translucent: Allow some light, but not clearly (butter paper, frosted glass).
- Opaque: Do not allow light to pass through (wood, metal, stone).
3) Light Travels in Straight Lines (Rectilinear Propagation)
Light generally travels in straight lines. This is why well-defined shadows form when an opaque object blocks light. It also explains why narrow beams form through small openings and why pinhole cameras create clear images.
4) Shadows – Formation and Features
A shadow is formed when an opaque object blocks light and a screen (such as a wall or the ground) receives the outline. Three basic requirements:
- A light source (Sun, torch, lamp)
- An opaque object (person, book, ball)
- A screen to catch the shadow (wall, ground, paper)
The shape of the shadow roughly matches the outline of the object. The size of a shadow depends on the distance between the object and the light source/screen:
- Closer object to the source → larger shadow on the screen.
- Farther object from the source → smaller shadow.
- Changing the angle of light changes the direction and length of the shadow.
5) Umbra and Penumbra (Simple Idea)
With larger light sources, you may notice a darker central region in the shadow (umbra) and a lighter outer region (penumbra). For Class 6, remember simply: bigger light source or closer object often gives a softer outer edge; smaller point-like source forms a sharper shadow.
6) Pinhole Camera (Basic Concept)
A basic pinhole camera is a closed box with a tiny hole on one side and a screen on the opposite side. Light from an object passes through the hole and forms an image on the screen. Key features of the image:
- Inverted (upside-down)
- Smaller or larger depending on distances
- Clearer if the hole is small and the box is still
7) Reflection of Light
Reflection is the bouncing back of light from a surface. Smooth, shiny surfaces (mirrors, calm water) give regular reflection, forming clear images. Rough surfaces scatter light in many directions (diffused reflection), giving blurred or no clear image.
8) Everyday Uses
- Shadows help estimate the position of the Sun and can be used in simple sundials.
- Pinhole camera demonstrates how images form without lenses.
- Mirrors are used in grooming, optical instruments, and safety reflectors.
- Translucent materials offer privacy while allowing light, useful for windows and lampshades.
9) Careful Observation
When experimenting with light, use everyday lamps or torches safely, keep materials stable, and avoid staring at intense sources. Gentle observation with simple setups is best for Class 6 learning.
📝 Questions & Answers – Practice Set
This section includes 7 MCQs (with choices), 7 Very Short, 7 Short, and 7 Long answer questions. Answers are provided just below each item for self-check.
Section A: Multiple Choice Questions (7)
1) Which of the following is a luminous object?
A) Moon B) Electric bulb (switched on) C) Book D) Wooden table
Answer: B) Electric bulb (switched on)
2) A material that allows most light to pass through is called:
A) Opaque B) Translucent C) Transparent D) Reflective
Answer: C) Transparent
3) A shadow is formed when:
A) Light bends around the object
B) Light passes through the object completely
C) An opaque object blocks light and a screen receives it
D) There is no screen
Answer: C) An opaque object blocks light and a screen receives it
4) In a pinhole camera, the image appears:
A) Upright B) Sideways C) Inverted D) Disappearing
Answer: C) Inverted
5) A plane mirror generally forms an image that is:
A) Smaller and inverted B) Same size and upright C) Larger and inverted D) Larger and upright
Answer: B) Same size and upright
6) A translucent material is best described as one that:
A) Blocks all light B) Allows some light, not clear images C) Allows all light clearly D) Emits light
Answer: B) Allows some light, not clear images
7) The left-right reversal seen in a mirror is called:
A) Diffusion B) Refraction C) Lateral inversion D) Shadowing
Answer: C) Lateral inversion
Section B: Very Short Answer Questions (7)
1) Define a luminous object.
Answer: An object that produces its own light.
2) Give one example of an opaque object.
Answer: Wood (e.g., a wooden door).
3) What is the essential condition to see a shadow?
Answer: An opaque object must block light and a screen must receive the outline.
4) Name the three classes of materials based on light transmission.
Answer: Transparent, translucent, and opaque.
5) What is a pinhole camera?
Answer: A simple box with a tiny hole that forms an inverted image on the opposite screen.
6) What is reflection?
Answer: The bouncing back of light from a surface.
7) State one property of an image in a plane mirror.
Answer: It is upright and of the same size as the object.
Section C: Short Answer Questions (7)
1) Differentiate between transparent and translucent materials with examples.
Answer: Transparent materials allow most light to pass, giving clear images (clean glass). Translucent materials allow some light but not clear images (frosted glass, butter paper).
2) Why does a shadow change size during the day?
Answer: The Sun’s position changes. When the Sun is low (morning/evening), shadows are long; when it is higher (around noon), shadows become shorter.
3) Explain why the Moon is visible though it is non-luminous.
Answer: The Moon reflects sunlight. We see it because light from the Sun bounces off the Moon and reaches our eyes.
4) How does the size of the pinhole affect the image in a pinhole camera?
Answer: A very small hole gives a sharper image but dimmer; a larger hole gives a brighter but blurred image.
5) What is lateral inversion?
Answer: In a plane mirror, the left-right reversal of an image compared to the object.
6) Can a transparent object form a shadow? Explain briefly.
Answer: Transparent objects usually form faint or no shadows because they let most light pass. Slightly tinted transparent objects may create very faint shadows.
7) State two differences between a shadow and an image in a mirror.
Answer: A shadow is a dark outline on a screen; it does not show color or detail. A mirror image shows details and colors and appears behind the mirror.
Section D: Long Answer Questions (7)
1) Describe the conditions required for shadow formation and the factors that affect its size and shape.
Answer: A shadow needs a light source, an opaque object, and a screen. The size depends on distances: moving the object closer to the source makes the shadow larger; farther makes it smaller. The angle of light changes the direction and length. The shape depends on the outline of the object; a tilted object can produce a differently shaped shadow.
2) Explain rectilinear propagation of light with everyday examples.
Answer: Light traveling in straight lines explains sharp shadows and the way beams from a torch form straight paths. Sunlight entering a room through a small hole creates a narrow, straight beam. Streetlights cast straight-edged shadows of poles, supporting the straight-line travel idea.
3) Discuss the working of a pinhole camera and the characteristics of the image formed.
Answer: A pinhole camera is a dark box with a tiny hole. Light from the top of the object passes through the hole and forms at the lower part of the screen; light from the bottom reaches the upper part. Hence the image is inverted. Image size depends on the distances between the object, hole, and screen. A smaller hole yields a sharper image; a larger hole increases brightness but reduces sharpness.
4) What is reflection? Differentiate between regular and diffused reflection with examples.
Answer: Reflection is the bouncing back of light from a surface. Regular reflection occurs on smooth surfaces (plane mirrors, calm water), producing clear images. Diffused reflection occurs on rough surfaces (paper, unpolished wood), scattering light in many directions and not forming a clear image. Everyday mirrors use regular reflection to give a clear view.
5) Give a detailed comparison: shadow vs. image in a mirror vs. image in a pinhole camera.
Answer: A shadow is a dark patch with the object’s outline, formed on a screen when light is blocked; it lacks color and internal detail. A mirror image is a visual result of regular reflection; it shows colors and details, is upright, same size, and appears behind the mirror with left-right reversal. A pinhole camera image is real and inverted, can be caught on a screen, and its size depends on distances and hole size.
6) How do transparent, translucent, and opaque materials influence light in daily life? Give examples and uses.
Answer: Transparent materials (window glass) let in daylight and allow clear viewing. Translucent materials (frosted glass) offer privacy while still admitting light, useful in bathrooms and lampshades. Opaque materials (doors, walls) block light to provide shade and separate spaces. Choosing the right type helps manage brightness, privacy, and comfort at home and school.
7) Describe simple classroom activities to understand shadows and reflection safely and clearly.
Answer: Use a torch, a small opaque object (like a toy), and a white wall or sheet. Change distances to observe shadow size. Place a small mirror upright and shine the torch to see the reflected beam on paper; adjust angles to notice direction change. Make a basic pinhole viewer using two cardboard pieces—one with a tiny hole, one as a screen—to see an inverted view of a bright object outdoors. Keep observations gentle and comfortable for the eyes.
🔎 Quick Recap
- Light enables vision; objects are seen by emitting or reflecting light.
- Materials are classified as transparent, translucent, or opaque by how they transmit light.
- Shadows form when opaque objects block light; size depends on distance and angle.
- Pinhole camera shows inverted images without lenses.
- Reflection from smooth surfaces produces clear images; rough surfaces scatter light.
- Mirror images are upright and same-sized but show left-right reversal.
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