Maharashtra Board Class 6 Science Chapter 14 Light and the Formation of Shadows Solutions

Std 6 Science Chapter 14 Light And The Formation Of Shadows Question Answer Maharashtra Board

Class 6 Science Chapter 14 Light And The Formation Of Shadows Question Answer Maharashtra Board

1. Choose An Appropriate Word And Fill In The Blanks.

Question a. A - is a natural source of light.
Answer: star
In simple words: Natural sources of light are objects that produce their own light, like the sun or stars.

🎯 Exam Tip: Identifying natural and artificial light sources is a fundamental concept for scoring well.

Question b. A - is an artificial source of light.
Answer: candle
In simple words: Artificial light sources are created by humans, such as a candle or an electric bulb.

🎯 Exam Tip: Distinguish between naturally occurring light and human-made light sources.

Question c. When light passes through a prism, it gets separated into - colours.
Answer: seven
In simple words: A prism splits white light into its constituent seven colors, a phenomenon known as dispersion.

🎯 Exam Tip: Remember the visible spectrum (VIBGYOR) when discussing light dispersion through a prism.

Question d. The image obtained in the pinhole camera is -.
Answer: inverted
In simple words: Due to the rectilinear propagation of light through a tiny hole, the image formed in a pinhole camera is always upside down.

🎯 Exam Tip: Understanding the inverted image in a pinhole camera is key to grasping light's straight-line travel.

Question e. A shadow is formed when an - object comes in the way of light.
Answer: opaque
In simple words: Shadows occur when an object that blocks light completely (opaque) is placed in the path of light, preventing light from reaching a surface behind it.

🎯 Exam Tip: The formation of shadows is directly linked to the opaque nature of an object.

Question f. When a - object comes in the way of light, light passes - it. options : seven, star, through, transparent, opaque, colors, shape, erect, inverted, luminous, candle.
Answer: transparent, through
In simple words: Transparent objects allow light to pass straight through them, which means no shadow is formed.

🎯 Exam Tip: Clearly differentiate between transparent, translucent, and opaque objects based on light passage.

2. Write Whether The Following Objects Are Luminous Or Non-Luminous.

Question a.

🎯 Exam Tip: Focus on whether an object is a primary source of light to classify it as luminous or non-luminous.

3. Match The Following.

Question a.

🎯 Exam Tip: Thoroughly understand the definitions and examples for natural/man-made sources and transparent/opaque/translucent materials.

4. Write The Answers To The Following.

Question a. What things are necessary for the formation of a shadow?
Answer: Things necessary for the formation of a shadow are:
1. A source of light
2. An object
3. A surface or screen on which the shadow is formed
In simple words: For a shadow to appear, you need light, something to block the light, and a surface for the shadow to fall upon.

🎯 Exam Tip: Remember these three key components; missing any one prevents shadow formation.

Question b. When can an object be seen?
Answer: We can see an object when reflected rays reach our eyes.
In simple words: We see objects because light bounces off them and enters our eyes.

🎯 Exam Tip: Emphasize reflection as the primary mechanism for seeing non-luminous objects.

Question c. What is a shadow?
Answer:
1. If an opaque object comes in the way of a light source, light does not pass through it.
2. As a result the light does not reach a wall or any other surface on the other side of the object.
3. That part remains dark. This dark part is called the shadow of the object.
In simple words: A shadow is the dark area formed when an opaque object blocks light, preventing it from reaching a surface behind it.

🎯 Exam Tip: A good definition includes the role of an opaque object and the resulting absence of light.

Project:

Question 1. Prepare a Newton's disc.
Answer: [No specific answer text is provided for this project question in the OCR. This is an activity.]
In simple words: A Newton's disc is a rotating disc with seven colors that, when spun fast, appear white, demonstrating that white light is made of seven colors.

🎯 Exam Tip: Understand that this project visually proves the composition of white light.

Question 2. Find out how to save electricity with the help of the sunlight we receive during the day.
Answer: [No specific answer text is provided for this project question in the OCR. This is an activity.]
In simple words: We can save electricity by maximizing the use of natural sunlight for lighting our homes during the day.

🎯 Exam Tip: Think about concepts like natural lighting, solar panels, and energy-efficient building designs.

Question 3. Read a biography of Sir C. V. Raman and find out about the discoveries he made.
Answer: [No specific answer text is provided for this project question in the OCR. This is an activity.]
In simple words: Sir C. V. Raman was an Indian physicist known for his work on the scattering of light, which led to the discovery of the Raman effect.

🎯 Exam Tip: Knowing about famous scientists like C.V. Raman enriches your understanding of physics history.

Class 6 Science Chapter 14 Light And The Formation Of Shadows Important Questions And Answers

Fill In The Blanks.

Question 1. The - is the main natural source of light.
Answer: Sun
In simple words: The Sun is our planet's most significant natural source of light and energy.

🎯 Exam Tip: Always remember the Sun as the primary natural light source.

Question 2. The light emitted by an electric torch is more - than that obtained from a candle.
Answer: intense
In simple words: An electric torch produces a brighter and more concentrated beam of light compared to a candle.

🎯 Exam Tip: Intensity of light relates to its brightness and how much light is emitted per unit area.

Question 3. The left and right sides of the original object appear to be - in the mirror.
Answer: exchanged
In simple words: When you look in a mirror, your left side appears as the right side of your reflection, and vice versa; this is called lateral inversion.

🎯 Exam Tip: Lateral inversion is a common characteristic of images formed by plane mirrors.

Question 4. The image is as far behind the mirror as the object is in - of it.
Answer: front
In simple words: In a plane mirror, the distance of the image from the mirror is equal to the distance of the object from the mirror.

🎯 Exam Tip: This property helps understand how plane mirrors form images.

Question 5. The - of the image is the same as that of the object.
Answer: height
In simple words: A plane mirror produces an image that is the same size as the actual object.

🎯 Exam Tip: Remember that plane mirrors do not magnify or reduce the size of the image.

Question 6. The materials through which light passes is said to be -.
Answer: transparent
In simple words: Transparent materials allow light to pass through them completely, letting us see clearly through them.

🎯 Exam Tip: Glass and clear water are common examples of transparent materials.

Question 7. The materials through which light does not pass is said to be -.
Answer: opaque
In simple words: Opaque materials block all light, preventing anything from being seen through them and casting distinct shadows.

🎯 Exam Tip: Wood and metal are typical examples of opaque objects.

Question 8. The materials through which light passes partially is said to be -.
Answer: translucent
In simple words: Translucent materials allow some light to pass through, but scatter it, making objects on the other side appear blurry or indistinct.

🎯 Exam Tip: Frosted glass or butter paper are good examples of translucent materials.

Question 9. If an - object comes in the way of a light source, light does not pass it.
Answer: opaque, through
In simple words: An opaque object completely blocks the path of light, which is why light cannot pass through it.

🎯 Exam Tip: This is a direct consequence of an opaque material's property of absorbing or reflecting all incident light.

Question 10. The shadow of an object formed due to sunlight is - in the mornings and evenings and - in the afternoon.
Answer: long, short
In simple words: Shadows are longer when the sun is low in the sky (morning/evening) and shorter when the sun is directly overhead (afternoon).

🎯 Exam Tip: The length of a shadow depends on the angle of the light source relative to the object.

Question 11. The shadow of an object is formed only when - does not pass through the object.
Answer: light
In simple words: Shadows form specifically because an object blocks the light from reaching a surface, creating an area of darkness.

🎯 Exam Tip: Without light being blocked, no shadow can be cast.

Question 12. Stars are -.
Answer: luminous
In simple words: Stars generate their own light through nuclear reactions, making them luminous objects.

🎯 Exam Tip: Stars are excellent examples of natural luminous objects.

Question 13. Planets, satellites are -.
Answer: non-luminous
In simple words: Planets and satellites do not produce their own light; they are visible because they reflect light from stars (like the Sun).

🎯 Exam Tip: Differentiate between self-luminous celestial bodies (stars) and reflective ones (planets, moons).

Question 14. The largest sundial is at -, New Delhi.
Answer: Jantar Mantar
In simple words: Jantar Mantar in New Delhi is an astronomical observatory containing giant sundials and other instruments.

🎯 Exam Tip: This is a factual question; remember the name of the famous sundial location.

Question 15. - is celebrated as National Science Day.
Answer: 28th February
In simple words: National Science Day is celebrated in India on February 28th to commemorate the discovery of the Raman Effect by Sir C. V. Raman.

🎯 Exam Tip: This date is significant for its connection to Indian scientific history.

Question 16. Light travels in a straight line. This is called -.
Answer: linear propagation of light
In simple words: The property of light to travel in a straight path is known as linear propagation.

🎯 Exam Tip: Linear propagation is a fundamental principle explaining phenomena like shadows and pinhole camera images.

Question 17. The image formed on the diaphragm of the pinhole camera is -.
Answer: inverted
In simple words: A pinhole camera creates an image that is flipped upside down due to light rays crossing at the tiny opening.

🎯 Exam Tip: Remember that a pinhole camera always produces an inverted (and real) image.

Question 18. The kind of shadow an object forms depends upon the -, - between the -, the object and the - or the - on which the shadow is formed.
Answer: relative distance, source of light, surface, screen
In simple words: The appearance of a shadow is influenced by how far the light source is, the type of light source, the object's distance from the screen, and the characteristics of the surface where the shadow appears.

🎯 Exam Tip: Factors affecting shadow size and sharpness include the size of the light source, the distance of the object from the source, and the object's distance from the screen.

State Whether Following Statements Are True Or False.

Question 1. Light travels in a straight line.
Answer: True
In simple words: Light always moves in straight paths unless it interacts with an object or a different medium.

🎯 Exam Tip: This is a fundamental property of light, essential for understanding optics.

Question 2. Stars are luminous.
Answer: True
In simple words: Stars emit their own light, classifying them as luminous objects.

🎯 Exam Tip: Reiterate the definition of luminous objects: those that produce light.

Question 3. Image in a pinhole camera is inverted.
Answer: True
In simple words: The image formed by a pinhole camera is always upside down because light rays cross at the pinhole.

🎯 Exam Tip: This characteristic is a key feature of pinhole camera images.

Question 4. In the afternoon, shadows are long.
Answer: False
In simple words: Shadows are shortest in the afternoon when the sun is highest in the sky.

🎯 Exam Tip: Relate shadow length to the sun's position (higher sun = shorter shadow).

Question 5. Fireflies are a natural source of light.
Answer: True
In simple words: Fireflies produce their own light through a chemical reaction called bioluminescence, making them natural light sources.

🎯 Exam Tip: Fireflies are unique examples of natural bioluminescent organisms.

Question 6. We see the candle clearly when we bend the tube.
Answer: False
In simple words: You cannot see a candle clearly through a bent tube because light travels in straight lines and cannot bend around corners.

🎯 Exam Tip: This illustrates the principle of linear propagation of light.

Question 7. We can see our image clearly in running water.
Answer: False
In simple words: Running water has an uneven, disturbed surface that scatters light irregularly, preventing a clear reflection or image from forming.

🎯 Exam Tip: Clear reflections require a smooth, calm surface, like still water or a mirror.

Question 8. Tracing paper is transparent.
Answer: False
In simple words: Tracing paper is translucent; it allows some light to pass through but diffuses it, making objects appear blurry.

🎯 Exam Tip: Distinguish between transparent (clear view) and translucent (blurry view).

Question 9. The light obtained from an electric torch is more intense than that obtained from a candle.
Answer: True
In simple words: An electric torch typically uses a more powerful and directed light source compared to the small flame of a candle.

🎯 Exam Tip: Intensity of light is a measure of its brightness or power.

Question 10. 28tn February is celebrated as "National Science day" since 1987 in India.
Answer: True
In simple words: This day honors the discovery of the Raman Effect and promotes scientific awareness in India.

🎯 Exam Tip: Knowing national science days links scientific concepts to cultural relevance.

Question 11. Classify the following into natural and man-made/artificial sources of light. (tubelight, light bulb, torch, burning candle, the sun, fireflies, anglerfish, honey mushroom, stars in the night sky, oil lamps, lanterns)
Answer:

🎯 Exam Tip: Be able to identify various examples for both categories clearly.

Question 12. Identify the transparent, opaque and translucent objects from among the following. (piece of glass, wax paper, tinted glass, oil paper, white plastic, a tea kettle, a notebook, cloth, water, a wooden cupboard, sheet of notebook.)
Answer:

🎯 Exam Tip: Practice classifying various everyday objects into these three categories based on their light transmission properties.

Question 13. Classify the following into the type of images they form: Clear image, faint image, no image. (still clear water, cemented wall, wooden surface, new steel dish, flower, glossy granite cladding of a wall, mirror, butter paper).
Answer:

🎯 Exam Tip: The clarity of an image depends directly on the smoothness and reflectivity of the surface.

Question 14. Relate images formed with the surfaces.
Answer:
1. The clear images are formed on plane surfaces.
2. Faint or no images are formed on rough surfaces.
In simple words: Smooth, flat surfaces create sharp, distinct images, while uneven surfaces result in blurry or absent reflections.

🎯 Exam Tip: This highlights the difference between regular reflection (smooth surface) and diffuse reflection (rough surface).

Answer In One Sentence.

Question 1. What are luminous objects?
Answer: The objects which emit light i.e. which themselves are a source of light, are called luminous objects.
In simple words: Luminous objects are those that produce and give off their own light.

🎯 Exam Tip: Provide common examples like the Sun, a light bulb, or a candle.

Question 2. What determines the intensity of light?
Answer: The intensity of light is determined by the extent to which the objects emit light.
In simple words: The brightness or strength of light is determined by how much light a source produces.

🎯 Exam Tip: Higher emission of light means higher intensity or brightness.

Question 3. What are non-luminous objects?
Answer: The objects that are not sources of light themselves are called as non-luminous objects.
In simple words: Non-luminous objects do not create light but rather reflect light from other sources.

🎯 Exam Tip: Mention examples such as planets, books, or tables to illustrate non-luminous objects.

Question 4. What are artificial sources of light?
Answer: Man-made objects which emit light are artificial sources of light.
In simple words: Artificial light sources are devices or objects created by humans that generate light.

🎯 Exam Tip: Focus on the "man-made" aspect when defining artificial sources.

Question 5. What are natural sources of light?
Answer: Natural substances, materials which emit light are called natural sources of light.
In simple words: Natural sources of light are objects that produce light without human intervention.

🎯 Exam Tip: The key differentiator is that these sources exist independently in nature.

Question 6. What is linear propagation of light?
Answer: Property of light travelling in a straight line is linear propagation of light.
In simple words: Linear propagation means that light always travels in a straight path or line.

🎯 Exam Tip: This property helps explain shadow formation and how a pinhole camera works.

Question 7. What is reflection of light?
Answer: The rays of light falling on an object from a source of light are thrown back from the substance of that object. This is reflection of light.
In simple words: Reflection of light is when light rays bounce off a surface.

🎯 Exam Tip: Differentiate between absorption and reflection of light by surfaces.

Question 8. How do we see objects around us?
Answer: The rays of light falling on an object from a source of light are thrown back from the surface of that object. This is called reflection of light. We see the object when the reflected rays reach our eyes.
In simple words: We see objects because light from a source hits them, bounces off (reflects), and then travels to our eyes.

🎯 Exam Tip: The process of seeing relies heavily on the reflection of light from objects.

Question 9. What is moonlight?
Answer: Sunlight reflected from the surface of the moon reaching us, in which we see the moon is called the moonlight.
In simple words: Moonlight is actually sunlight that is reflected off the Moon's surface and then travels to Earth.

🎯 Exam Tip: Remember that the Moon itself is not a source of light; it's a reflector.

Question 10. What type of image is formed in the mirror?
Answer: The image formed in the mirror is 'laterally inverted' i.e. right side appears as left side and left side appears as right side.
In simple words: A plane mirror forms an image that is laterally inverted, meaning left and right are swapped, but it is upright and the same size as the object.

🎯 Exam Tip: Lateral inversion is a specific term for the left-right reversal in a mirror image.

Question 11. What change do you see in the image if you decrease or increase your distance from the mirror?
Answer: When the distance between object and mirror is increased the size of image decreases where as, when the distance is decreased the image size increases.
In simple words: As you move closer to a mirror, the image appears larger; as you move farther away, it appears smaller.

🎯 Exam Tip: This effect is more pronounced in concave/convex mirrors than in plane mirrors, where image size is constant, but perspective changes.

Question 12. What difference do you find in the height of the image in the mirror and yourself?
Answer: The size of the image in the mirror is the same as that of the object.
In simple words: In a plane mirror, the reflected image is always the same height as the actual object.

🎯 Exam Tip: Plane mirrors do not magnify or diminish the object's height.

Question 13. What is the image on the diaphragm of the pinhole camera?
Answer: An inverted or an upside down image of the candle is seen on the diaphragm of the pinhole camera.
In simple words: The image formed inside a pinhole camera is always upside down and real.

🎯 Exam Tip: The inverted nature is a defining characteristic of pinhole camera images.

Question 14. What do you mean by transparent object?
Answer: The objects / materials through which light passes are said to be transparent.
In simple words: A transparent object allows light to pass through it completely, letting you see clearly through it.

🎯 Exam Tip: Clear glass and water are classic examples of transparent materials.

Question 15. What do you mean by opaque materials?
Answer: The materials through which light does not pass are said to be opaque.
In simple words: Opaque materials completely block light and do not allow it to pass through.

🎯 Exam Tip: Understanding opaque objects is crucial for explaining shadow formation.

Question 16. What do you mean by translucent materials?
Answer: The materials through which light passes partially are said to be translucent.
In simple words: Translucent materials allow some light to pass through, but scatter it, making objects on the other side appear blurry.

🎯 Exam Tip: Understanding the difference between transparent, opaque, and translucent objects is fundamental for light-related questions.

Question 17. How is the shadow in the morning, afternoon and evening?
Answer: The shadows are long in the mornings and evenings and short in the afternoon.
In simple words: Shadows are long during sunrise and sunset because the sun is low in the sky, and shortest at midday when the sun is highest.

🎯 Exam Tip: Relate the sun's position to shadow length; a lower sun creates longer shadows.

Question 18. What is shade of a tree?
Answer: The shade of a tree is its shadow.
In simple words: The shade under a tree is simply the area where the tree blocks sunlight, creating its shadow.

🎯 Exam Tip: A shadow is formed when an opaque object blocks light, creating a dark area.

Question 19. How many colours is sunlight made up of?
Answer: Sunlight is made up of seven colours.
In simple words: White sunlight, when dispersed, reveals seven distinct colours: Red, Orange, Yellow, Green, Blue, Indigo, and Violet.

🎯 Exam Tip: Remember the VIBGYOR sequence (Violet, Indigo, Blue, Green, Yellow, Orange, Red) for the colours of the visible light spectrum.

Give Reasons For The Following

Question 1. When we see in the mirror, we see our image in the mirror.
Answer: When we see our face in the mirror, the light reflected from our face falls on the mirror and gets reflected back again. Hence, we see our image in the mirror.
In simple words: We see our reflection in a mirror because light from our face hits the mirror, bounces off, and enters our eyes, creating an image.

🎯 Exam Tip: Reflection is key to seeing images in mirrors; smooth surfaces provide clear reflections.

Question 2. Opaque materials cast shadow.
Answer: An opaque material does not allow light to pass. Hence, it casts a shadow.
In simple words: Opaque objects block light completely, preventing it from passing through, which results in the formation of a shadow behind them.

🎯 Exam Tip: Opaque objects are essential for shadow formation; translucent or transparent objects do not create clear shadows.

Question 3. Transparent and translucent object do not cast a shadow.
Answer: Translucent objects cast a faint shadow whereas transparent objects do not cast a shadow at all because they allow light to pass through them.
In simple words: Transparent objects let all light pass, so no shadow forms; translucent objects let some light through, creating only a faint, blurry shadow.

🎯 Exam Tip: The degree to which an object blocks light directly determines the characteristics of its shadow.

Use Your Brain Power!

Question 1. Why is the image on the diaphragm of the pinhole camera inverted?
Answer:1. The pinhole camera works on the principle of light travelling in a straight line. 2. The rays of light from the candle flame go in all directions. 3. We consider only two rays that pass through the hole and fall on the screen.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक पिनहोल कैमरे की कार्यप्रणाली को दर्शाता है। इसमें एक मोमबत्ती से निकलने वाली प्रकाश की किरणें एक छोटे छेद (पिनहोल) से गुजरकर पीछे की स्क्रीन (पतले कागज) पर एक उलटा प्रतिबिंब बनाती हैं। यह प्रकाश के सीधी रेखा में गमन के सिद्धांत को स्पष्ट करता है। 4. The rays intersect at the pinhole. 5. Since the rays cross over at that point, the top of the object appears at the bottom of the image and the bottom of the image appears at the top. Thus, we see an inverted image of the candle.
In simple words: In a pinhole camera, light rays cross at the tiny opening. Because the top rays go to the bottom and bottom rays go to the top, the image formed on the screen is upside down or inverted.

🎯 Exam Tip: The principle of linear propagation of light and the crossing of light rays at the pinhole are crucial to explain image inversion.

Question 2. How will you light up a dark room using reflected light?
Answer: Focusing on the wall with torch light. Mirrors or reflectors can be used to get light from outside.
In simple words: To light up a dark room using reflected light, you can use mirrors or other reflective surfaces to redirect sunlight or torch light from outside into the room.

🎯 Exam Tip: Mirrors are effective reflectors and can be strategically placed to illuminate dark areas by bouncing light.

Question 3. Try to start the TV by operating the remote control from behind it.
Answer: T.V will not start.
In simple words: The TV will not start because the remote control needs a clear, unobstructed path to send its infrared signal directly to the TV's sensor.

🎯 Exam Tip: Remote controls use infrared light, which travels in straight lines and cannot pass through opaque objects like the TV itself.

Question 4. In which step is the flame of the candle seenclearly? Why?
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र प्रकाश के सीधी रेखा में गमन (linear propagation) के सिद्धांत को दर्शाता है। पहले चरण में व्यक्ति एक सीधी नली से मोमबत्ती की लौ को स्पष्ट रूप से देख रहा है, जबकि दूसरे चरण में नली मुड़ी हुई है और लौ दिखाई नहीं दे रही है। यह सिद्ध करता है कि प्रकाश सीधी रेखा में चलता है।
Answer: In step 1 the flame of the candle is seen clearly because light travels in straight line.
In simple words: The candle flame is clearly seen in Step 1 because the viewing tube is straight, allowing light to travel directly from the flame to the eye.

🎯 Exam Tip: This experiment demonstrates the fundamental property of light: it always travels in a straight line.

Can You Tell?

Question 1. Can we see anything in total darkness?
Answer: No, we cannot see anything in total darkness.
In simple words: Without any light, there is nothing for our eyes to detect, so we cannot see in total darkness.

🎯 Exam Tip: Vision requires light to be reflected from objects and enter our eyes.

Question 2. What helps us to see the objects around us?
Answer: Reflected light helps us to see objects around us.
In simple words: We see objects when light from a source hits them and bounces off (reflects) into our eyes.

🎯 Exam Tip: Reflection is a crucial phenomenon that enables us to perceive the world around us.

Question 3. What does the light in each one of the pictures originate form?
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र प्रकाश के चार विभिन्न स्रोतों को दर्शाता है: एक जलता हुआ बल्ब (मानव निर्मित), एक जुगनू (प्राकृतिक), एक जलती हुई मोमबत्ती (मानव निर्मित) और सूर्य (प्राकृतिक)। ये स्रोत हमें प्रकाश प्रदान करते हैं। 1. Bulb 2. Firefly 3. Candle 4. Sun
In simple words: The light originates from an incandescent bulb, a bioluminescent firefly, a burning candle, and the sun, representing both artificial and natural light sources.

🎯 Exam Tip: Be able to differentiate between natural light sources (like the sun and fireflies) and artificial ones (like bulbs and candles).

Question 4. Name the natural sources of light.
Answer: Sun, Fireflies
In simple words: Natural sources of light are those that produce light on their own, like the sun and fireflies.

🎯 Exam Tip: Natural sources are not man-made and emit light through natural processes.

Question 5. In which objects do we see our reflection?
Answer: All objects reflect light rays, but the best reflectors of light are mirrors, still water in a lake, new steel dish i.e. smooth shiny surfaces.
In simple words: We see clear reflections in very smooth, shiny surfaces like mirrors, calm water, and polished metal because they reflect light uniformly.

🎯 Exam Tip: The smoothness and shininess of a surface directly influence the clarity of the reflection seen.

Question 6. What difference do you notice on looking through the windows in the picture? What causes the difference? The picture shows transperant, opaque, translucent window panes. Spot them.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र तीन अलग-अलग प्रकार की खिड़कियों को दर्शाता है जो विभिन्न सामग्रियों से बनी हैं। पहली खिड़की पारदर्शी है जिससे बाहर का स्पष्ट दृश्य दिखता है, दूसरी अर्ध-पारदर्शी है जो धुंधला दृश्य देती है, और तीसरी अपारदर्शी है जिससे कुछ भी दिखाई नहीं देता है।
Answer:1. Through the first window we can see a clear picture of things outside. 2. Second window gives a faint image. 3. Through the third window, we can't see anything 4. The difference in the image is due to the material of the window panes. 5. The first window pane is transparent. 6. The second window pane is translucent. 7. The third window pane is opaque.
In simple words: The windows show clear (transparent), faint (translucent), and no view (opaque) because of the different light-passing properties of their materials.

🎯 Exam Tip: Differentiating between transparent, translucent, and opaque materials based on how they interact with light is a key concept.

Answer The Following Questions In Brief.

Question 1. List factors on which shadow depends.
Answer: Shadow depends on relative distance between the source of light, the object and the surface on which the shadow is formed.
In simple words: The characteristics of a shadow depend on how far the light source is, the object's position, and the distance to the surface where the shadow appears.

🎯 Exam Tip: Remember these three factors: source of light, object, and screen, as they are crucial for shadow formation and characteristics.

Question 2. How we can see that light travels in straight line.
Answer:1. In the morning or in the afternoon, rays of light enter a slit in a door, window or a small hole in the roof. 2. As these rays of light from the slit or the hole move towards the floor, the dust particles in their way are clearly seen. 3. Due to these particles, the path of light becomes visible to us. 4. Thus we can see that their path is along straight lines.
In simple words: We can observe light travelling in straight lines by seeing dust particles illuminated in sunbeams entering a room through small openings.

🎯 Exam Tip: The visibility of dust particles in a light beam is a classic example demonstrating the linear propagation of light.

Question 3. What is the difference between an object and its reflection? What causes the difference?
Answer:1. Object and its reflection result in formation of images. 2. Reflections taking place from highly polished metals, mirrors, still water etc, form clear images. 3. Reflections taking place from wooden surface, flower, book form dull, blurred images. 4. The difference in reflections is caused by the surface of the object. 5. Regular reflections have smooth, polished surfaces, hence, image is clear. 6. Diffused reflections have hard, rough surfaces, hence, image is dull.
In simple words: Objects are real entities, while reflections are images formed by light bouncing off a surface; the clarity of the reflection depends on whether the surface is smooth (clear image) or rough (dull image).

🎯 Exam Tip: Distinguish between regular reflection (from smooth surfaces) and diffused reflection (from rough surfaces) as the cause for image clarity differences.

Question 4. List characteristics of images in a plane mirror.
Answer:1. The left and right sides of the original object appear to be exchanged in the mirror image. 2. The image is as far behind the mirror as the object is in front of it. 3. The size of the image is the same as that of the object.
In simple words: A plane mirror forms an image that is laterally inverted (left-right swapped), the same size as the object, and appears to be as far behind the mirror as the object is in front.

🎯 Exam Tip: Key characteristics of plane mirror images include lateral inversion, virtual nature, same size, and equal object-image distance.

Question 8. State the characteristics of image formed by a pinhole camera.
Answer: Characteristics of an image formed by a pinhole camera are as follows: 1. It is inverted/upside down. 2. It can be obtained on a screen – real image.
In simple words: The image formed by a pinhole camera is always inverted (upside down) and is a real image, meaning it can be projected onto a screen.

🎯 Exam Tip: Remember that pinhole camera images are real and inverted, contrasting with the virtual and laterally inverted images of plane mirrors.

Try This.

Question 1. Make your friend stand in between the torch and the wall. What happens?
Answer: Friend's Shadow forms on the wall.
In simple words: When your friend stands between a light source and a wall, their body blocks the light, creating a shadow of their shape on the wall.

🎯 Exam Tip: This illustrates shadow formation, where an opaque object obstructs light from reaching a surface.

Question 2. Place a glass filled with water on a sheet of paper in the window so it receives direct sunlight. What is seen on the paper?
Answer: We see rainbow colours on the paper.
In simple words: When sunlight passes through a water-filled glass, it acts like a prism, splitting the white light into its component rainbow colours, which are then seen on the paper.

🎯 Exam Tip: This experiment demonstrates the dispersion of light, where white light separates into its constituent colours when passing through a medium like water or a prism.

Question 3. Can we do the same in a dark room with the help of a prism and a torch? What do we learn from this?
Answer: yes, we can. Light gets seperated into seven colour. From this we learn that white light contains seven colours.
In simple words: Yes, a prism and a torch in a dark room can also separate white torch light into seven colours, teaching us that white light is composed of these distinct colours.

🎯 Exam Tip: The experiment confirms that white light, whether from the sun or a torch, is a mixture of seven spectral colours.

Question 4. If you dip the wire loop in the soap water and then blow it, soap bubbles are formed. Are the beautiful colours of the rainbow seen in these bubbles?
Answer: Yes, splitting of white light into different colours takes place.
In simple words: Yes, soap bubbles display rainbow colours due to light interacting with the varying thickness of the soap film, causing interference and splitting white light into its spectrum.

🎯 Exam Tip: The iridescent colours of soap bubbles are caused by the phenomenon of light interference and dispersion.

Question 5. What do you see on holding a CD in the sun?
Answer: CD reflects rainbow colours, and interesting - patterns.
In simple words: When a CD is held in the sun, its microscopic grooves diffract light, splitting white sunlight into its various colours and creating a rainbow effect along with intricate patterns.

🎯 Exam Tip: A CD's surface acts as a diffraction grating, demonstrating how light can be separated into its colours through interference and diffraction.

Question 6. Raise your right hand. In mirror which hand of the mirror image is raised?
Answer: Left hand of the mirror image is raised.
In simple words: When you raise your right hand, your mirror image appears to raise its left hand due to lateral inversion.

🎯 Exam Tip: Lateral inversion is a key property of plane mirrors where the image is flipped horizontally.

Question 7. Is there any difference between your height and height of the mirror image?
Answer: The height remains the same.
In simple words: There is no difference in height between you and your mirror image; a plane mirror produces an image of the same size.

🎯 Exam Tip: A plane mirror always forms an image that is the same size as the object.