CLASS 8 PHYSICS LIGHT

<p>Away from the normal (A)</p> Signup and view all the answers

<p>Light travels slower in water, causing it to bend (C)</p> Signup and view all the answers

<p>Speed of light decreases in denser medium (D)</p> Signup and view all the answers

<p>The Earth's atmosphere refracts sunlight, bending it towards the observer (D)</p> Signup and view all the answers

<p>Refraction (D)</p> Signup and view all the answers

<p>Mirage (D)</p> Signup and view all the answers

<p>Refraction of light through different air layers (D)</p> Signup and view all the answers

<p>The rays bend towards the normal (C)</p> Signup and view all the answers

<p>The light rays are reflected (D)</p> Signup and view all the answers

<p>Dispersion (C)</p> Signup and view all the answers

<p>Spectrum (C)</p> Signup and view all the answers

<p>Brown (B)</p> Signup and view all the answers

<p>They form a white color (A)</p> Signup and view all the answers

<p>The angle of incidence is equal to the angle of reflection (C)</p> Signup and view all the answers

<p>Pole (C)</p> Signup and view all the answers

<p>Focus (C)</p> Signup and view all the answers

<p>Focal Length (B)</p> Signup and view all the answers

<p>Convex Mirror (C)</p> Signup and view all the answers

<p>Concave Mirror (A)</p> Signup and view all the answers

<p>Convex Mirror (B)</p> Signup and view all the answers

<p>Concave Mirror (A)</p> Signup and view all the answers

<p>Convex Mirror (B)</p> Signup and view all the answers

<p>Refraction of light (B)</p> Signup and view all the answers

<p>The angle of incidence is the angle between the incident ray and the normal. (D)</p> Signup and view all the answers

<p>The speed of light decreases as the density of the medium increases. (A)</p> Signup and view all the answers

<p>It bends away from the normal. (C)</p> Signup and view all the answers

<p>The slower the light travels, the more it bends. (D)</p> Signup and view all the answers

<p>Refracted ray (B)</p> Signup and view all the answers

<p>Refraction of light (B)</p> Signup and view all the answers

<p>They bend away from the normal (B)</p> Signup and view all the answers

<p>The light rays meet at a point (B)</p> Signup and view all the answers

<p>C and P (D)</p> Signup and view all the answers

<p>Virtual and smaller (D)</p> Signup and view all the answers

<p>When the object is outside the center of curvature (D)</p> Signup and view all the answers

<p>By displaying a wider field of view (B)</p> Signup and view all the answers

<p>They reflect back along their original path (B)</p> Signup and view all the answers

<p>Distance from the pole to the focus (D)</p> Signup and view all the answers

<p>It is always zero (C)</p> Signup and view all the answers

<p>Erect and enlarged (A)</p> Signup and view all the answers

<p>Combining colors to appear white (D)</p> Signup and view all the answers

<p>Used in headlights (C)</p> Signup and view all the answers

<p>The water refracts the light rays coming from the stick, causing them to bend away from the normal and reach our eyes from a different position. (A)</p> Signup and view all the answers

<p>The Earth's atmosphere refracts the sunlight, bending the light rays towards the normal and extending the apparent sunset. (A)</p> Signup and view all the answers

<p>The speed of light decreases as the density of the medium increases. (B)</p> Signup and view all the answers

<p>The speed of light decreases, and the ray bends towards the normal. (C)</p> Signup and view all the answers

<p>The angle of refraction is always greater than the angle of incidence. (C)</p> Signup and view all the answers

<p>When the air near the ground is warmer than the air above it, causing light rays to bend upwards. (D)</p> Signup and view all the answers

<p>Light travels faster in a denser medium than in a rarer medium. (A)</p> Signup and view all the answers

<p>The refraction of light as it passes from the water to the air causes the pencil to appear bent. (B)</p> Signup and view all the answers

<p>The convex mirror reflects the light rays outward, causing them to appear to converge at a point behind the mirror. (C)</p> Signup and view all the answers

<p>The triangular cross section causes the white light to refract at different angles, separating it into its constituent colors. (D)</p> Signup and view all the answers

<p>Concave mirrors can magnify images. (D)</p> Signup and view all the answers

<p>Convex mirrors always form virtual images, which are smaller than the object. (D)</p> Signup and view all the answers

<p>The angle of incidence at the center of curvature is always 90 degrees. (B)</p> Signup and view all the answers

<p>Differences in the density of air layers caused by temperature variations. (B)</p> Signup and view all the answers

<p>Violet (C)</p> Signup and view all the answers

<p>Between the pole and the focus. (D)</p> Signup and view all the answers

<p>Convex mirrors diverge light rays, causing the image to appear smaller. (B)</p> Signup and view all the answers

<p>Concave mirrors can converge parallel light rays to a point. (B)</p> Signup and view all the answers

<p>A ray of light striking a mirror at a 60-degree angle, with the reflected ray making a 30-degree angle with the normal. (B)</p> Signup and view all the answers

<p>The difference in the wavelength of light in different colors. (A)</p> Signup and view all the answers

<p>It can spread the light from the lamp over a wider area. (B)</p> Signup and view all the answers

<p>The angle of incidence is always equal to the angle of reflection. (A)</p> Signup and view all the answers

<p>Real images can be projected onto a screen, while virtual images cannot. (A)</p> Signup and view all the answers

<p>The colors are moving so fast that they blend together, creating the appearance of white light. (C)</p> Signup and view all the answers

<p>The sun's rays are refracted by the earth's atmosphere, causing the sun to appear higher in the sky than it actually is. (D)</p> Signup and view all the answers

<p>The air near the water gets cooler and denser, causing the light rays to bend upwards, making the boat appear higher. (B)</p> Signup and view all the answers

<p>The speed of light is inversely proportional to the density of the medium; as density increases, the speed decreases. (B)</p> Signup and view all the answers

<p>The speed of light decreases, and the ray bends towards the normal. (C)</p> Signup and view all the answers

<p>The angle of refraction will be less than 30 degrees, because water is denser than air, causing the light to bend towards the normal. (D)</p> Signup and view all the answers

<p>The light rays from the stick are refracted as they pass from water to air, causing the apparent bend. (A)</p> Signup and view all the answers

<p>The angle of incidence increases as the light moves from the denser medium to the rarer medium, leading to an increase in the angle of refraction until it reaches 90 degrees. (B)</p> Signup and view all the answers

<p>Dispersion, Spectrum (C)</p> Signup and view all the answers

<p>equal to, lie (C)</p> Signup and view all the answers

<p>it converges light rays, it diverges light rays (B)</p> Signup and view all the answers

<p>A concave mirror forms a virtual image when the object is placed between the pole and the focus, and a real image otherwise. (A)</p> Signup and view all the answers

<p>It forms virtual images, providing a wider field of view. (A)</p> Signup and view all the answers

<p>The distance between the pole of the mirror and the focus. (B)</p> Signup and view all the answers

<p>The seven colors blend together to create the illusion of white light. (A)</p> Signup and view all the answers

<p>The change in the density of the air layers caused by the temperature difference. (C)</p> Signup and view all the answers

<p>back along its own path (C)</p> Signup and view all the answers

<p>The refraction of light as it passes from water to air causes the stick to appear bent. (D)</p> Signup and view all the answers

<p>The angle of incidence is greater than the angle of refraction, and the speed of light increases. (B)</p> Signup and view all the answers

<p>Violet, Indigo, Blue, Green, Yellow, Orange, Red (A)</p> Signup and view all the answers

<p>A convex mirror, because it reflects light rays outward, ensuring the image is virtual and smaller. (B)</p> Signup and view all the answers

<p>The pole is the geometric center of the spherical reflecting surface, and the center of curvature is the center of the sphere from which the mirror is a part. (A)</p> Signup and view all the answers

<p>The reflected rays converge behind the mirror, creating a virtual image that appears larger. (C)</p> Signup and view all the answers

<p>It reflects the light rays in multiple directions, providing a wider area of illumination. (C)</p> Signup and view all the answers

<p>speed</p> Signup and view all the answers

<p>denser</p> Signup and view all the answers

<p>transparent</p> Signup and view all the answers

<p>incident</p> Signup and view all the answers

<p>angle</p> Signup and view all the answers

<p>towards</p> Signup and view all the answers

<p>warmer</p> Signup and view all the answers

<p>above</p> Signup and view all the answers

<p>mirage</p> Signup and view all the answers

<p>rarer</p> Signup and view all the answers

<p>dispersion</p> Signup and view all the answers

<p>VIBGYOR</p> Signup and view all the answers

<p>spectrum</p> Signup and view all the answers

<p>centre of curvature</p> Signup and view all the answers

<p>radius of curvature</p> Signup and view all the answers

<p>convex</p> Signup and view all the answers

<p>convex</p> Signup and view all the answers

<p>concave</p> Signup and view all the answers

<p>convex</p> Signup and view all the answers

<p>concave</p> Signup and view all the answers

<p>real</p> Signup and view all the answers

<p>concave</p> Signup and view all the answers

<p>centre of curvature</p> Signup and view all the answers

<p>direction</p> Signup and view all the answers

<p>direction</p> Signup and view all the answers

<p>normally</p> Signup and view all the answers

<p>towards</p> Signup and view all the answers

<p>obliquely</p> Signup and view all the answers

<p>mirage</p> Signup and view all the answers

<p>refraction</p> Signup and view all the answers

<p>rarer</p> Signup and view all the answers

<p>denser</p> Signup and view all the answers

<p>dispersion</p> Signup and view all the answers

<p>VIBGYOR</p> Signup and view all the answers

<p>spectrum</p> Signup and view all the answers

<p>white</p> Signup and view all the answers

<p>pole</p> Signup and view all the answers

<p>centre of curvature</p> Signup and view all the answers

<p>converge</p> Signup and view all the answers

<p>head</p> Signup and view all the answers

<p>field</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>The stick appears bent due to the refraction of light as it travels from water to air. The light rays from the submerged part of the stick bend away from the normal as they enter the less dense air, causing the stick to appear bent.</p> Signup and view all the answers

<p>This is due to the bending of sunlight through layers of air with different densities. The warmer air near the ground is less dense than the cooler air above, causing the sunlight to bend upwards, creating the illusion of the sun being higher in the sky.</p> Signup and view all the answers

<p>The speed of light is slower in denser mediums. The denser a medium is, the more the light particles interact with the medium's particles, slowing the light down.</p> Signup and view all the answers

<p>Light rays bend towards the normal when traveling from a rarer medium (where it travels faster) to a denser medium (where it travels slower).</p> Signup and view all the answers

<p>A normal is an imaginary line drawn perpendicular to the surface separating two mediums, at the point where the light ray hits the surface. The angles of incidence and refraction are measured relative to this normal.</p> Signup and view all the answers

<p>Density variations in air cause light rays to bend. Warm air is less dense, causing light to bend away from the normal, while cooler air is denser, causing light to bend towards the normal. This bending can create mirages, where objects appear to be in different locations than they actually are.</p> Signup and view all the answers

<p>An incident ray is the ray of light that strikes the surface of a medium. The refracted ray is the ray that results after the light has been bent as it enters the new medium. The normal is an imaginary line perpendicular to the surface at the point of incidence. The angles of incidence and refraction are measured from the normal.</p> Signup and view all the answers

<p>Mirage</p> Signup and view all the answers

<p>In deserts, the hot sand heats the air near the ground, making it less dense. Light rays from an object, like a tree, travel from the denser, cooler air above to the rarer, warmer air below. This causes them to bend away from the normal, leading to a false image that appears like a pool of water.</p> Signup and view all the answers

<p>Dispersion of light</p> Signup and view all the answers

<p>Violet, indigo, blue, green, yellow, orange, red</p> Signup and view all the answers

<p>The seven colors of the visible spectrum (VIBGYOR) are the constituent colors of white light. When these colors are combined, they blend together to produce a perception of white light.</p> Signup and view all the answers

<ol> <li>Angle of incidence equals angle of reflection. 2. The incident ray, reflected ray, and normal all lie in the same plane.</li> </ol> Signup and view all the answers

<p>Focus</p> Signup and view all the answers

<p>Focal length</p> Signup and view all the answers

<p>A concave mirror produces a magnified image of the object placed between its pole and focus. This magnification allows for a clearer view when shaving or examining a patient.</p> Signup and view all the answers

<p>Convex mirrors have a wider field of view than a plane mirror, allowing the driver to see more of the area behind them.</p> Signup and view all the answers

<p>Convex mirrors always form a virtual, erect, and diminished image. The image appears smaller than the object.</p> Signup and view all the answers

<p>After reflection from a concave mirror, parallel light rays converge at a point called the focus.</p> Signup and view all the answers

<p>The angle of incidence is equal to the angle of reflection.</p> Signup and view all the answers

<p>Light bends towards the normal when it travels from a rarer medium (air) to a denser medium (water) because the speed of light decreases in the denser medium.</p> Signup and view all the answers

<p>The speed of light is inversely proportional to the density of the medium. This means that light travels slower in denser mediums and faster in rarer mediums.</p> Signup and view all the answers

<p>A mirage is formed when the air near the ground is hotter than the air above. Hot air is less dense, causing light to travel faster. As light rays from the sky pass through the hot air near the ground, they bend upwards, making it appear as if there is a reflecting surface of water on the ground.</p> Signup and view all the answers

<p>This phenomenon is caused by the refraction of light in the atmosphere. The rays of sunlight pass through the Earth's atmosphere, which is denser near the surface. As light passes from the rarer atmosphere above to the denser atmosphere below, the light bends towards the normal, making the sun appear higher than it actually is.</p> Signup and view all the answers

<p>Glass is optically denser than air, which means light travels slower in glass. As the light slows down when entering the glass, it bends towards the normal to maintain a constant frequency.</p> Signup and view all the answers

<p>The refractive index of a medium is the ratio of the speed of light in a vacuum to the speed of light in that medium. A higher refractive index indicates a slower speed of light and a denser medium.</p> Signup and view all the answers

<p>The air near the ground in a desert is much hotter than the air above. This creates layers of varying density, with the hotter air being less dense. Light rays from the sky pass through these layers, bending upwards as they travel from denser to rarer air. This bending creates the illusion of a reflecting surface, resulting in the mirage.</p> Signup and view all the answers

<p>A mirage is a visual illusion caused by the refraction of light through layers of air with different densities. In a desert, the hot sand heats the air near the ground, making it less dense than the cooler air above. This difference in density causes light rays to bend as they pass through the layers. The bending of light can create an image of a reflecting pool of water beneath the sky, as the light from the sky appears to be reflected off the ground, giving the false impression of a water body.</p> Signup and view all the answers

<p>Dispersion is the splitting of white light into its constituent colors when it passes through a prism. This happens because each color of light has a different wavelength and bends at a slightly different angle as it passes through the denser medium of the prism. The resulting spectrum, arranged from bottom to top, is: Violet, Indigo, Blue, Green, Yellow, Orange, and Red (VIBGYOR).</p> Signup and view all the answers

<p>A rapidly rotating disc appears white because the colors of the segments blend together due to the persistence of vision. Our eyes retain the image of an object for a short duration, and when the disc spins quickly, the colors blend together, creating the effect of white light. This is because white light is essentially the combination of all the colors of the visible spectrum.</p> Signup and view all the answers

<p>The two laws of reflection of light are:</p> <ol> <li><strong>The angle of incidence is equal to the angle of reflection.</strong></li> <li><strong>The incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.</strong></li> </ol> Signup and view all the answers

<p><strong>Pole (P):</strong> The geometric center of the spherical surface of the mirror. <strong>Center of Curvature (C):</strong> The center of the sphere of which the mirror is a part. <strong>Radius of Curvature (R):</strong> The radius of the sphere of which the mirror is a part. <strong>Principal Axis:</strong> A straight line joining the pole of the mirror to its center of curvature.</p> Signup and view all the answers

<p>The focal point (F) of a concave mirror is a point on the principal axis where parallel rays of light incident on the mirror converge after reflection. It is formed because the rays reflected from the mirror converge at a single point.</p> Signup and view all the answers

<p>The focal point (F) of a convex mirror is a point on the principal axis where parallel rays of light incident on the mirror appear to diverge from after reflection. It is formed because the reflected rays diverge, and an observer looking at the mirror would see the rays as if they were coming from a focal point behind the mirror.</p> Signup and view all the answers

<p>A convex mirror always forms a virtual, erect, and diminished image. The image is virtual meaning it cannot be projected onto a screen. It is also upright and smaller than the object.</p> Signup and view all the answers

<p>A concave mirror forms a real image when the object is placed beyond the focal point. In this case, the reflected rays actually converge to form the image, which is an inverted and magnified image. The image is also real because it can be projected onto a screen.</p> Signup and view all the answers

<p>A concave mirror is used as a shaving mirror because it produces a magnified and upright virtual image when the object is placed between the pole and focus of the mirror. This allows the user to see a magnified view of their face, making it easier to shave.</p> Signup and view all the answers

<p>A convex mirror is used as a rearview mirror in cars because it provides a wider field of view than a plane mirror. This allows the driver to see a larger area of the road behind them, including traffic in the side lanes, increasing their visibility and safety.</p> Signup and view all the answers

<p>Dentists use concave mirrors because they can be used to focus light. When a beam of light is incident parallel to the principal axis of a concave mirror, the reflected rays converge at the focal point. This concentrates the light into a smaller area, allowing the dentist to illuminate the teeth effectively and see them more clearly.</p> Signup and view all the answers

<p>Convex mirrors are used as reflectors in street lamps because they diverge the light rays incident on them. This causes the light to spread out more broadly, illuminating a wider area and increasing the effectiveness of the street lamp.</p> Signup and view all the answers

<p>When a straight stick is partially submerged in water, it appears bent due to the refraction of light. Light travels at different speeds through water and air. When light passes from the water to the air, it bends away from the normal, causing the stick to appear bent at the point where it enters the water.</p> Signup and view all the answers

<p>The sun appears to be above the horizon even after it has set due to atmospheric refraction. As sunlight passes through the Earth's atmosphere, it is bent slightly due to changes in air density. This bending causes the sun to appear higher in the sky than it actually is, making it seem as if it is above the horizon even after it has set.</p> Signup and view all the answers

<p>When light travels from a rarer medium (air) to a denser medium (water), it slows down. This decrease in speed causes the light to bend towards the normal at the point where it enters the water. The normal is an imaginary line perpendicular to the surface of the water.</p> Signup and view all the answers

<p>This phenomenon is called atmospheric refraction. As the sun sets, its light passes through the Earth's atmosphere at an angle. The lower layers of the atmosphere are denser than the upper layers, causing the light to bend towards the normal as it enters the denser layers. This bending continues as the light travels through the atmosphere, causing the sun to appear above the horizon even after it has set.</p> Signup and view all the answers

<p>This illusion occurs due to the refraction of light. When the light from the submerged part of the stick travels from water (a denser medium) to air (a rarer medium), it bends away from the normal. This change in direction makes the stick appear bent at the surface of the water. The normal is an imaginary line perpendicular to the surface of the water, and the bending of light occurs in relation to this line.</p> Signup and view all the answers

<p>The speed of light is inversely related to the optical density of a medium. If light travels slower in a medium, it is considered optically denser. Conversely, if light travels faster in a medium, it is considered optically rarer.</p> Signup and view all the answers

<p>When light travels from a denser medium to a rarer medium, it bends away from the normal. This is because the speed of light increases as it enters the rarer medium.</p> Signup and view all the answers

<p>When light travels from a rarer medium to a denser medium, its speed decreases. This change in speed causes the light to bend towards the normal. The normal is an imaginary line perpendicular to the boundary between the two media, and the light bends in relation to this line.</p> Signup and view all the answers

<p>A mirage is an optical illusion caused by atmospheric refraction. When light travels from a hot, less dense layer of air to a colder, denser layer, it bends towards the normal as it passes through the boundary. This bending of light can create an illusion of a reflecting surface, such as a pool of water in a desert.</p> Signup and view all the answers

<p>One scenario is the mirage in a desert, where the bending of light due to different air densities creates an illusion of water. The other is the apparent position of the sun above the horizon during sunset or sunrise, caused by the bending of sunlight as it passes through the Earth's atmosphere.</p> Signup and view all the answers

<p>A mirage occurs due to the bending of light rays as they travel through layers of air with different densities. In a desert, the hot sand heats the air near the ground, making it less dense than the cooler air higher up. Light rays from the sky travel from the denser, cooler air to the rarer, hotter air. This causes them to bend away from the normal, leading to a gradual upward curvature. When these bent rays reach the eye of the observer, they appear to be coming from a point below the ground, creating the illusion of a reflective water surface.</p> Signup and view all the answers

<p>Dispersion of light is the phenomenon where white light is split into its constituent colors when it passes through a prism. This happens because each color of light has a different wavelength and bends at a different angle as it passes through the prism. The shorter wavelengths, like violet, bend the most, while the longer wavelengths, like red, bend the least. This results in a spectrum of colors, with violet at the bottom and red at the top. The order of the colors in the spectrum is Violet, Indigo, Blue, Green, Yellow, Orange, Red, often remembered by the acronym VIBGYOR.</p> Signup and view all the answers

<p>A rapidly rotating white disc appears white because the different colored segments merge together so quickly that our eyes perceive them as a single color. This is because white light is actually a combination of all the colors of the rainbow. When we see a rotating disc with colored segments, our eyes receive the colors in rapid succession. Due to the persistence of vision, our eyes blend these colors together, creating a perception of white light. This is just like how a prism separates the colors of white light, when we blend them back together, they appear white.</p> Signup and view all the answers

<p>Concave mirrors are curved inward, resembling a spoon's inside surface. They converge parallel light rays to a point called the focal point, which lies in front of the mirror. They can produce both real and virtual images depending on the object's position, with real images formed when the object is beyond the focal point. Convex mirrors, on the other hand, curve outward like the back of a spoon. They diverge parallel light rays, making the focal point appear to be behind the mirror. Convex mirrors always form virtual, upright, and smaller images compared to the object.</p> Signup and view all the answers

<p>A concave mirror is used as a shaving mirror because it forms an enlarged, upright, virtual image when the object is placed between the pole and the focus. This allows for a magnified view of the face during shaving. Convex mirrors, on the other hand, are used as rearview mirrors in vehicles due to their ability to provide a wider field of view. They always form smaller, upright, virtual images, enabling the driver to see a larger area behind the vehicle, minimizing blind spots.</p> Signup and view all the answers

<p>A dentist utilizes a concave mirror to concentrate a beam of light onto a specific area of the teeth by positioning the mirror so that the parallel light rays entering the mirror converge at the focal point. This focusing effect creates a strong beam of light concentrated on the teeth, enabling the dentist to clearly examine small details and cavities. The concentrated light allows for enhanced visibility, increasing accuracy and effectiveness during dental procedures.</p> Signup and view all the answers

<p>Convex mirrors are used as street light reflectors because they diverge the incoming light rays, effectively spreading the light over a broader area. This wide illumination is beneficial for illuminating a larger portion of the street, improving visibility and safety for pedestrians and drivers. Compared to other mirror types, convex mirrors offer the advantage of wider illumination due to their diverging nature, ensuring that more of the street is well-lit.</p> Signup and view all the answers

<p>Reflection is the process where light bounces back from a smooth surface when it strikes it. The two fundamental laws of reflection are: 1) The angle of incidence (the angle between the incident ray and the normal) is equal to the angle of reflection (the angle between the reflected ray and the normal); and 2) The incident ray, the reflected ray, and the normal to the reflecting surface all lie in the same plane.</p> Signup and view all the answers

<p>A real image is formed when reflected light rays actually converge at a point, enabling it to be projected onto a screen. These images are always inverted. Virtual images, on the other hand, are formed when the reflected rays appear to diverge from a point behind the mirror, meaning they cannot be projected onto a screen. Virtual images are always upright.</p> Signup and view all the answers

<p>The speed of light changes as it travels from one medium to another because the density of each medium affects how light interacts with its constituent particles. When light enters a denser medium like water or glass, it encounters more particles and interacts more with them, slowing down. This change in speed causes the light to bend, which is the phenomenon we know as refraction. The denser the medium, the slower the light travels, and the more it bends.</p> Signup and view all the answers

<p>The angle of incidence and the angle of refraction are related by Snell's law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the indices of refraction of the two media. When light travels from a denser medium to a rarer medium, it bends away from the normal. This means that the angle of refraction is greater than the angle of incidence.</p> Signup and view all the answers

<p>Focal length is the distance between the pole of a mirror and its focus, the point where parallel light rays converge or appear to converge after reflection. In concave mirrors, the focal length is positive, indicating that the focus is in front of the mirror. In convex mirrors, the focal length is considered negative, implying that the focus is behind the mirror.</p> Signup and view all the answers

<p>A ray of light passing through the center of curvature of a spherical mirror is reflected along its own path because it strikes the mirror's surface at a perpendicular angle. This angle of incidence is zero, meaning the reflected ray also makes a zero-degree angle with the normal, causing it to retrace its original path. This is due to the fundamental law of reflection that states the angle of incidence is equal to the angle of reflection.</p> Signup and view all the answers

<p>A convex mirror is used as a driver's rearview mirror due to its ability to provide a wide field of view. It forms a smaller, upright, virtual image that encompasses a larger area behind the vehicle, minimizing blind spots. This enables drivers to see a wider range of traffic behind them, improving their awareness and safety on the road. The smaller image size doesn't compromise the visibility of distant objects, enhancing overall driving safety.</p> Signup and view all the answers

<p>The type of image formed by a concave mirror depends on the position of the object relative to its focal point. When the object is placed beyond the center of curvature (C), a real, inverted, and diminished image is formed. When the object is between C and F, a real, inverted, and magnified image is formed. However, when the object is placed between the pole (P) and the focal point (F), a virtual, upright, and magnified image is formed. Concave mirrors can produce both real and virtual images because their converging nature allows for different image formations based on the object's location.</p> Signup and view all the answers

<p>Refraction is the bending of light as it passes from one medium to another with a different density. When a stick is partially submerged in water, light rays traveling from the water to the air bend away from the normal, causing the submerged portion of the stick to appear higher than its actual position. This visual effect is due to the difference in the speed of light in water and air, which causes the light rays to change direction at the surface, resulting in a distorted perception of the stick's true shape and location.</p> Signup and view all the answers

The speed of light travels at 3 x 10^8 m s-1 in air.

The speed of light travels at 2.25 x 10^8 m s-1 in water.

The speed of light travels at 2 x 10^8 m s-1 in glass.

A medium where the speed of light decreases, indicating it is denser.

A medium where the speed of light increases, indicating it is rarer.

The change in direction of light when it passes from one medium to another.

The ray of light that strikes the surface of a medium.

The angle between the incident ray and the normal line.

An optical illusion of water seen in deserts caused by light refraction.

Bending of light as it passes through materials of different densities.

The splitting of white light into its constituent colors as it passes through a prism.

The colored band produced when white light passes through a prism.

An acronym for the seven colors of the spectrum: Violet, Indigo, Blue, Green, Yellow, Orange, and Red.

1. Angle of incidence equals angle of reflection; 2. Incident ray, reflected ray, and normal lie in the same plane.

The geometric center of the spherical surface of a mirror.

The center of the sphere from which the mirror is made.

The point where parallel light rays converge after reflection.

The point where parallel light rays appear to diverge from after reflection.

Forms an erect, virtual, and enlarged image when the object is between the pole and focus.

Always forms a small, erect image that is virtual.

An image formed when reflected rays actually meet at a point.

1. Shaving mirror; 2. Doctor's head mirror.

1. Rear view mirror; 2. Street lamp reflector.

Light slows down when entering a denser medium, like water from air.

When light moves from a rarer to a denser medium, it bends towards the normal.

Light bends away from the normal when passing from a denser to a rarer medium.

The angle between the refracted ray and the normal line is the angle of refraction (r).

An imaginary line perpendicular to the surface at the point of incidence between two media.

Water is optically denser than air since light travels slower in water.

Sun appears above the horizon before sunrise due to light refraction through air layers.

A straight stick looks bent when partially submerged in water due to light refraction.

An upside-down image seen in a mirage.

Air layers in deserts: hot near ground, cooler above.

The distance from the focus to the pole of the mirror.

The point where parallel rays meet in a concave mirror.

The point where parallel rays appear to diverge in a convex mirror.

An image formed when the reflected rays actually converge.

An image that cannot be projected on a screen; appears behind the mirror.

Rays passing through the center of curvature reflect back along their path.

The geometric center of a spherical mirror.

The part of a mirror where silvering is done to enable reflection.

Concave mirrors are used because they can show enlarged images.

Convex mirrors provide a wider view, allowing drivers to see more behind them.

In denser mediums, light bends towards the normal due to speed decrease.

In rarer mediums, light bends away from the normal as speed increases.

The ray of light that changes direction after entering a different medium.

When light bends at the surface, like when the sun appears above the horizon early.

Water is denser than air because light travels slower in water.

As light travels from denser to rarer media, its angle of refraction increases until it reaches 90°.

When the angle of incidence becomes 90°, the light ray is reflected, not refracted.

The mirage gives a false impression of a pool of water, seen as an inverted image of an object.

A prism is a transparent medium with triangular cross-sections that splits light into colors.

The splitting of white light into seven colors when passing through a prism.

The colored band (VIBGYOR) produced when white light passes through a prism.

The distance from the focus to the pole in a spherical mirror.

A straight line joining the pole of a mirror to its center of curvature.

A convex mirror always creates a small, erect, virtual image of objects.

Concave mirrors are used in shaving and dental mirrors to enlarge images.

Convex mirrors diverge incident light rays, creating virtual images for wider views.

The angle of incidence equals the angle of reflection; they mirror each other.

A ray passing through the center of curvature reflects back along its path.

In concave mirrors, parallel light rays converge at the focus after reflection.

Light slows down in denser mediums and speeds up in rarer ones.

Light changes direction when it passes from one medium to another.

The ray of light that strikes the boundary between two media.

The ray of light that has changed direction in the new medium.

Light bends towards the normal in denser media and away in rarer media.

A medium is denser if light speed decreases and rarer if it increases.

The sun appears above the horizon due to light refraction at sunrise/sunset.

A mirage is created by the refraction of light in hot air layers, creating an illusion of water.

Refraction occurs when light travels from a denser to a rarer medium, bending away from the normal.

A prism splits white light into its constituent colors due to dispersion.

The spectrum is the band of colors seen when white light is dispersed by a prism; includes VIBGYOR.

The straight line connecting the pole of a mirror to its center of curvature.

A concave mirror creates an erect, enlarged image when the object is between the pole and focus.

A ray passing through the center of curvature reflects back along its original path.

Concave mirrors are used as shaving mirrors because they focus light on a small area.

A medium where light speed decreases, making it denser.

A medium where light speed increases, indicating it's rarer.

Light bends towards the normal in dense media and away in rarer media.

An imaginary line perpendicular to the surface at the point of light incidence.

A medium is denser if light slows down; rarer if it speeds up.

The sun appears above the horizon due to light bending during sunrise and sunset.

When the angle of incidence reaches 90°, light reflects instead of refracting.

Converges parallel light rays to a focal point after reflection.

Diverges light rays, creating virtual images that appear smaller.

Point where parallel rays converge in concave or appear to diverge in convex mirrors.

Concave mirrors create erect and enlarged images when the object is between pole and focus.

Always forms an erect, smaller, and virtual image.

Used in shaving mirrors and as doctor's head mirrors for focused light.

The angle of incidence is equal to the angle of reflection in mirror reflection.

A mirror made by silvering a hollow glass sphere, having a silvered and reflecting surface.

The radius of the sphere from which a spherical mirror is made.

An image formed by converging reflected rays that can be projected on a screen.

An image formed when light rays appear to converge but don't actually meet.

A measure of how much light slows down in a given medium.

The bending of light when it moves through different media.

An optical phenomenon caused by the refraction of light in hot air, creating a false image of water.

Mirage is formed when light rays bend due to temperature differences in air layers.

Refraction occurs when light passes from a denser to a rarer medium, bending away from the normal.

A prism disperses white light into seven colors known as VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange, Red.

The incident ray, reflected ray, and normal all lie in the same plane during reflection.

Concave mirrors create erect and enlarged images when objects are placed between the pole and focus.

The ray of light that strikes a surface prior to reflection or refraction.

A mirror made by reflecting on a spherical surface, with a silvered and reflecting side.

Convex mirrors form erect, virtual images that enable a wider view behind the surface.

Refraction is the change in direction of light when it passes from one medium to another.

As light travels from a denser to a rarer medium, its angle of refraction increases until it reaches 90°.

The process where white light is split into its constituent colors by passing through a prism.

A mirror made by silvering a part of a hollow glass sphere, reflecting from the back surface.

Water is optically denser than air due to slower light speed in water.

Air is optically rarer than glass because light travels faster in air.

When light hits normally, the angle of incidence is 0°.

Light bends towards the normal when entering a denser medium.

Light bends away from the normal when moving to a rarer medium.

A straight stick in water appears bent due to refraction of light.

The sun appears above the horizon before sunrise due to refraction of light.

Upper layers of air are rarer due to being warmer than lower layers.

A convex mirror always forms a small, erect, and virtual image.

The angle of incidence equals the angle of reflection in any reflection scenario.

Concave mirrors converge light rays and are used for magnifying features like in shaving mirrors.

Convex mirrors diverge light rays and provide wider fields of view, useful for safety mirrors like in vehicles.

The angle between the incident ray and the normal when light strikes a surface.

An imaginary line perpendicular to the surface at the point of light incidence between two media.

When light moves from a rarer medium to a denser medium, it bends towards the normal.

When light transitions from a denser medium to a rarer medium, it bends away from the normal.

Convex mirrors diverge incident light rays, creating virtual images that appear smaller.

The sun appears above the horizon due to refraction of its light through atmospheric layers.

Light changes direction when moving between mediums of different densities, causing bending.

Concave mirrors form erect, virtual, and enlarged images between the pole and focus.

Convex mirrors always create small, erect, and virtual images.