- A. curved line, shadows
- B. straight line, shadows
- C. straight line, reflection
- D. curved line and then straight line, shadows
(b) straight line, shadows
- A. Transmitted
- B. Reflected
- C. Absorbed
- D. Refracted
(b) Reflected
- A. Water
- B. Compact disc
- C. Mirror
- D. Stone
(c) Mirror
- A. matter
- B. energy
- C. medium
- D. partical
(b) energy
- A. regular reflection takes place in wooden table and irregular reflection in polished floor
- B. regular reflection takes place in polished floor and irregular reflection in wooden table
- C. regular reflection takes place in both polished floor and wooden table
- D. irregular reflection takes place in both polished floor and wooden table
You can see your image in polished floors but not in wooden tables because polished floors have a smooth, even surface that causes regular reflection of light. In regular reflection, parallel rays of light reflect in the same direction, allowing a clear and distinct image to form. In contrast, wooden tables have a rough and uneven surface with many tiny irregularities. This causes irregular or diffuse reflection, where parallel rays of light reflect in many different directions. As a result, the reflected light scatters randomly and no clear image is formed. Therefore, regular reflection in polished floors produces a visible image, while irregular reflection in wooden tables does not.
- A. glass
- B. wood
- C. water
- D. Clouds
(d) clouds
- A. about to reach a surface
- B. approaches a surface
- C. passes through a surface
- D. None Of these
(b) approaches a surface
- A. light travels in straight lines
- B. light rays become laterally inverted as they pass through a pinhole camera
- C. light rays pass through the pinhole
- D. light rays get reflected
(a) light travels in straight lines
- A. Light travels in straight lines
- B. Opaque bodies do not allow light to pass through them
- C. Reflection occurs at a smooth surfaces like mirrors
- D. Lateral inversion happens
- A. both A and B
- B. both A and D
- C. both B and C
- D. only A
Shadows are formed due to the fact that light travels in straight lines and cannot bend around objects. When an opaque object is placed in the path of light from a source, the light is blocked and cannot pass through the object. This creates a dark region called a shadow on the surface behind the object. The shadow is formed on the opposite side of the object from the light source. The size and shape of the shadow depend on the position and distance of the light source from the object, as well as the distance of the object from the surface where the shadow falls. Both the property that light travels in straight lines and the property that opaque objects block light are essential facts that explain how shadows are formed.
Rainbow is formed by dispersion of white light by water drops. When sunlight enters water droplets in the atmosphere, it slows down and bends. Different colors of white light have different wavelengths and bend by different amounts, causing them to separate. This separation of white light into its component colors is called dispersion. As the light exits the water droplet, it bends again and the colors spread out further, creating the spectrum of colors we see as a rainbow.
False
Correct statement: The image formed by the plane mirror is laterally inverted, hence the image seen through the periscope is This is because in periscope, image is reflected by two mirrors.
True
True. We see a book because it reflects the light that falls on its surface. When light from a source such as the sun or a lamp strikes the book, the light reflects off the book's surface. This reflected light enters our eyes, allowing us to see the book and read the text on its pages.
True. The image formed in a pinhole camera is always inverted. Light from an object passes through the small pinhole opening and travels in straight lines. The light rays from the top of the object pass through the pinhole and strike the bottom of the screen, while rays from the bottom strike the top of the screen. This crossing of light rays causes the image to be inverted both vertically and horizontally.
False. The image formed in a pinhole camera is not always the same size as the object. The size of the image depends on the distance of the object from the pinhole and the distance of the screen from the pinhole. If the object is closer to the pinhole, the image will be smaller, and if the object is farther from the pinhole, the image will be larger. Therefore, the image size varies with these distances.
False. The correct statement is: The image formed in a plane mirror is erect. A plane mirror produces an image that is upright and the same size as the object. The image appears to be behind the mirror at a distance equal to the distance of the object in front of the mirror. Although the image is laterally inverted, it is not upside down.
True
False. The correct statement is: A shadow is formed on the opposite side of the object from the source of light. When light from a source strikes an opaque object, the light is blocked and cannot reach the surface behind the object. This creates a shadow on the side away from the light source. The shadow always appears on the side of the object that faces away from the light source.
True. We are able to see things around us with the help of regular reflection. Most objects in our environment have surfaces that cause regular reflection of light. When light reflects regularly off these surfaces, it reaches our eyes in an organized manner, allowing us to see the objects clearly and perceive their shapes, colors, and details.
True. When white light passes through a prism, it undergoes dispersion and splits into a band of seven colours. These colours are violet, indigo, blue, green, yellow, orange, and red, commonly remembered by the acronym VIBGYOR. Each colour has a different wavelength and refractive index, which causes them to bend at different angles when passing through the prism, resulting in the separation of white light into its component colours.
1. Rectilinear propagation Pinhole camera 2. Rectilinear propagation Periscope 3. Plane Mirror Firefly luminous object 4. The Moon Non-luminous object 5. Wide light source Penumbra 6. Regular reflection Glossy surface 7. The sun Primary source of light 8. Band of seven colors Spectrum of light. These matchings demonstrate key concepts in light and optics. Rectilinear propagation refers to light travelling in straight lines, which is the principle behind both the pinhole camera and periscope. A plane mirror reflects light regularly and is used in a firefly's light production mechanism. The Moon is a non-luminous object that reflects sunlight. A wide light source creates a penumbra or partial shadow region. Regular reflection occurs on glossy surfaces. The sun is a primary source of light. When white light disperses through a prism, it produces a spectrum of seven colours.
Laws of reflection:The angle of incidence is always equal to the angle of reflection li =l*
The incident ray, the reflected ray and the normal at the point of incidence lie on the same plane.
Distance between the person and the mirror = 3.5 m
Distance between the person and tree (object) = 0.5 m
The image formed in the mirror = 4 m
The distance between the image of the tree and his eyes = 4 + 3.5 = 7.5
Luminous objects are all objects which emit light energy by themselves. These objects produce their own light through various processes such as combustion, incandescence, or chemical reactions. Examples of luminous objects include the sun, which produces light through nuclear fusion, electric bulbs, which produce light through heating of a filament, candles, which produce light through combustion, and fireflies, which produce light through bioluminescence. Non-luminous objects, in contrast, do not produce their own light and can only be seen when light from a luminous source falls on them and gets reflected.
No, the moon is not a luminous object. The reason is that the moon does not produce its own light. Instead, it reflects the light of the sun falling on its surface. The moon is therefore a non-luminous object that appears bright in the night sky only because of the sunlight reflected from its surface. We can see the moon because the reflected sunlight reaches our eyes. The brightness of the moon depends on the position of the sun and moon relative to Earth, which is why the moon appears to have different phases throughout the month.
The three types of materials based on the absorption and transmission of light are transparent materials, translucent materials, and opaque materials. Transparent materials allow light to pass through them completely, so objects on the other side can be seen clearly. Examples include clear glass, water, and air. Translucent materials allow some light to pass through but scatter it, so objects on the other side cannot be seen clearly. Examples include frosted glass, tracing paper, and thin cloth. Opaque materials do not allow light to pass through them at all, so objects on the other side cannot be seen. Examples include wood, metal, and brick.
The two parts of a shadow are the umbra and the penumbra. The umbra is the darkest central part of the shadow where light from the source is completely blocked by the opaque object. The penumbra is the lighter outer region of the shadow where light from the source is partially blocked. The penumbra forms only when the light source is large or extended. When the light source is a point source, only the umbra is formed and there is no penumbra.
The properties of shadow are as follows. All objects do not form shadows; only opaque objects form shadows because they completely block the passage of light. Shadows are always formed on the opposite side of the light source. The characteristics of an object cannot be determined by its shadow alone, as different objects may cast similar shadows. The shadow is always darker than the surrounding area, regardless of the colour of the light rays falling on it. The light source, opaque object, and shadow are always in a straight line, which demonstrates the rectilinear propagation of light. The size of the shadow depends upon the distance between the light source and the object, as well as the distance between the object and the screen. When the object is closer to the light source, the shadow is larger, and when the object is farther from the light source, the shadow is smaller. Similarly, when the object is closer to the screen, the shadow is smaller, and when the object is farther from the screen, the shadow is larger.
Visible light is a spectrum of a number of waves with different wavelength range from 400nm to 700nm (lnm = 10″9 meter) each wave has a definite wavelength represents a particular colour.
Sources of Light: Stars, electric light bulb, candle, planets. Objects that reflect light: Brick walls, plants, mirror. Stars and planets are both sources of light, though stars produce their own light while planets reflect light from the sun. Electric light bulbs and candles are luminous objects that produce light. Brick walls, plants, and mirrors are non-luminous objects that reflect light falling on them. Mirrors reflect light regularly, while brick walls and plants reflect light diffusely.
- A. The distance between the boy and his image is ______
- B. The height of the image is ______
- C. When the boy moves 1 m forward, the distance between her and her image is ______
(a) The distance between the boy and his image is 4m
(b) The height of the image is same.
(c) When the boy moves 1 m forward, the distance between her and her image is 2m.
The writing on the front of an ambulance is back to front due to the phenomenon of lateral inversion. Lateral inversion is the phenomenon due to which the left side of an object appears to be the right side in its image in a reflecting medium like a mirror. When drivers look in their rear-view mirrors, they see the ambulance behind them. Due to lateral inversion, the reversed writing appears correct in the mirror. This allows drivers to read the word 'AMBULANCE' correctly in their rear-view mirror and immediately recognize that an ambulance is approaching from behind, enabling them to give way to the emergency vehicle.
Some capital letters look the same in a mirror while others are reversed because of bilateral symmetry. Letters that have bilateral symmetry, meaning they are identical on both sides of a vertical line through their centre, will have their mirror image appear the same as the original letter. Examples of such symmetrical letters include A, H, I, M, O, T, U, V, W, X, and Y. These letters look identical when reflected in a mirror. In contrast, letters like B, C, D, E, F, G, J, K, L, N, P, Q, R, S, and Z do not have bilateral symmetry and therefore appear reversed or different in a mirror image.
BC, CD
AB, BC
\(\lfloor i\) = 39°
\(\lfloor r\) = 39°
Angle of incidence \(\lfloor i\) = 90° – 50°
\(\lfloor i\) = 40°
According to laws of reflection,
\(\lfloor i\) = \(\lfloor k\)
Angle of incidence = Angle of reflection
\(\lfloor i\) = 40°
∴ \(\lfloor r\) – 40°
Angle of reflection \(\lfloor r\) = 40°
Lateral inversion is the phenomenon due to which the left side of an object appears as the right side and the right side appears as the left side in its image formed by a plane mirror. This occurs because a plane mirror reverses the direction of light rays perpendicular to its surface. When you look at yourself in a mirror, your left hand appears on the right side of the mirror image and your right hand appears on the left side. This is why writing and images appear reversed or back to front when reflected in a mirror.
A spectrum of light is obtained by passing white light through a prism. When white light is made to fall on the surface of a prism at an angle, it undergoes refraction and dispersion. The different colours in white light have different wavelengths and refractive indices, causing them to bend at different angles as they pass through the prism. This separation of white light into its component colours produces a spectrum of light, which displays the seven colours: violet, indigo, blue, green, yellow, orange, and red. The spectrum can be observed on a white screen placed on the other side of the prism.
When Newton's disc is rotated very fast, the different colors of the spectrum on the disc move so quickly that the human eye cannot distinguish between them individually. The retina of the eye receives the sensation of all the spectrum colors simultaneously and continuously. Since all the colors of the visible spectrum are present on the disc, when they blend together in this rapid motion, our eyes perceive them as white light. This happens because white light is composed of all the colors of the spectrum combined together. The persistence of vision in the human eye causes the colors to merge, and we see the disc as white rather than as separate colored segments. This phenomenon demonstrates that white light is indeed a combination of all visible colors.
(i) Regular reflection When a parallel beam of light on striking some smooth and polished surface is reflected as a parallel beam of light, such a reflection is called regular reflection.(ii) Irregular reflection : When a parallel beam of light, on striking some rough surface, is reflected in different directions, then such a reflection is called irregular or diffused reflection.
Luminous objects are all objects which emit light energy by themselves. These objects produce their own light through various processes such as combustion, incandescence, or chemical reactions. Non-luminous objects are all objects which do not emit light energy of their own, but reflect the light energy falling on them and hence become visible. These objects are visible only because they reflect light from luminous sources. Examples of luminous objects include the Sun, stars, electric bulbs, torches, and burning candles. Examples of non-luminous objects include the Moon, planets, trees, houses, stones, metals, and most everyday objects we see around us. The key difference is that luminous objects are sources of light, while non-luminous objects are visible only because they reflect light from other sources.
One everyday situation that demonstrates light travels in a straight line is the formation of shadows. When an opaque object is placed in front of a light source, a shadow forms on the opposite side. This shadow has a sharp outline and is formed because light rays travel in straight lines and cannot bend around the object. The rays that hit the object are blocked, while the rays that pass around the edges continue in straight lines, creating the distinct shadow shape. Another everyday situation is when light enters a dark room through a small hole or window. The light beam entering through the hole travels in a straight line, creating a bright patch on the opposite wall or surface. If you observe the path of sunlight coming through a window on a dusty day, you can see the light traveling in a straight line through the dust particles in the air. These observations clearly show that light does not curve or bend on its own but travels in straight paths.
Reflection and shadow are two different phenomena related to light. Reflection occurs when light falls on a smooth, polished surface such as a mirror or still water. The direction of the light ray is changed at the surface, following the law of reflection where the angle of incidence equals the angle of reflection. A reflected image is formed that appears to come from behind the mirror. For example, when you look at yourself in a mirror or see your reflection in a pool of water, you are observing reflection. A shadow, on the other hand, is formed when light is blocked by an opaque object. It is an image formed by the obstruction of light, showing only the outline or silhouette of the object. For example, if you place your hand in front of a candle, you will see the shadow of your hand on the wall behind it. The shadow shows only the outline of the object and is always formed on the side opposite to the light source. Unlike a reflection, a shadow does not show details or colors of the object, only its shape.
The image formed in a plane mirror has several important characteristics. First, the image is upright or erect, meaning it is in the same orientation as the object. Second, the image is virtual, which means it cannot be projected onto a screen as it appears to be behind the mirror rather than in front of it. Third, the image is of the same size as the object, so there is no magnification or reduction. Fourth, the distance of the image from the plane mirror is equal to the distance of the object from the mirror. If an object is placed 10 centimeters in front of a mirror, its image will appear 10 centimeters behind the mirror. Fifth, the image is laterally inverted, meaning the left and right sides of the object are reversed in the image. For example, if you raise your right hand, your reflection appears to raise its left hand. These characteristics make plane mirrors useful for everyday applications such as personal grooming and seeing objects behind us.
- A. Incident ray
- B. Reflected ray
- C. Normal
- D. Angle of incidence
The following are important terms related to reflection of light. Incident ray is the ray of light that falls on the surface of the reflecting material. It is the incoming light ray that strikes the mirror or reflective surface. Reflected ray is the ray of light that comes from the point where the incident ray falls on the reflecting material. It is the outgoing light ray that bounces off the mirror after reflection. Normal is the perpendicular line drawn from the point of incidence to the plane of the reflecting surface. It serves as a reference line for measuring angles in reflection. Angle of incidence is the angle formed between the incident ray and the normal at the point of incidence. It is measured from the normal to the incident ray. Angle of reflection is the angle formed between the reflected ray and the normal at the point of incidence. It is measured from the normal to the reflected ray. According to the law of reflection, the angle of incidence is always equal to the angle of reflection.
Pinhole camera and plane mirror both form images, but these images have several important differences. The image formed by a pinhole camera is real, meaning it can be projected onto a screen or surface, whereas the image formed in a plane mirror is virtual and cannot be projected. In a pinhole camera, the image may not be equal to the size of the object and is often smaller or larger depending on the distance between the object and the camera, while in a plane mirror, the image is always equal in size to the object. The image formed by a pinhole camera is inverted, appearing upside down, whereas the image formed in a plane mirror is erect or upright in the same orientation as the object. Additionally, a pinhole camera requires a screen to display the image, while a plane mirror shows the image directly when you look into it. The pinhole camera works on the principle that light travels in straight lines, while a plane mirror works on the principle of reflection of light.
(i)(ii)(iii) 3 letters (E,N,S)
(iv) I,T