Solution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.1P<\/strong>
\nAlaserbeam is reflected by a plane mirror. Itis observed that the angle between the incident and reflected beams is 28\u00b0. If the mirror is now rotated so that the angle of incidence increases by 5.0\u00b0, what is the new angle between the incident and reflected beams?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.2CQ<\/strong>
\nTwo plane mirrors meet at right angles at the origin, as indicated in Figure. Suppose an L-shaped object has the position and orientation labeled B. Draw the location and orientation of all the images of object B formed by the two mirrors.
\n
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.2P<\/strong>
\nThe reflecting surfaces of two mirrors form a vertex with an angle of 120\u00b0. If a ray of light strikes mirror 1 with an angle of incidence of 55\u00b0, find the angle of reflection of the ray when it leaves mirror 2.
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.3CQ<\/strong>
\nWhat is the radius of curvature of a plane mirror? What is its focal length? Explain.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.3P<\/strong>
\nA ray of light reflects from a plane mirror with an angle of incidence of 37\u00b0. If the mirror is rotated by an angle \u03b8, through what angle is the reflected ray rotated?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.4CQ<\/strong>
\nDish receivers for satellite TV always use the concave side of the dish, never the convex side. Explain.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.4P<\/strong>
\nIP Asmall vertical mirror hangs on the wall, 1.40 m above the floor. Sunlight strikes the mirror, and the reflected beam forms a spot on the floor 2.S0 m from the wall. Later in the day, you notice that the spot has moved to a point 3.75 m from the wall. (a) Were your two observations made in the morning or in the afternoon? Explain. (b) What was the change in the Sun\u2019s angle of elevation between your two observations?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.5CQ<\/strong>
\nSuppose you would like to start a fire by focusing sunlight onto a piece of paper. In Conceptual Checkpoint 26-2 we saw that a concave mirror would be better than a convex mirror for this purpose. At what distance from the mirror should the paper be held for best results?
\nSolution:<\/strong><\/span>
\nA fire can be started by focusing sunlight onto a piece of paper. For this purpose, a concave mirror is preferred over a convex mirror, because, when the light rays strike a concave mirror, it gets reflected and meets at the focal point of the mirror. Whereas, the reflected rays from a convex mirror diverge from the mirror, and appear as they come from the focal point behind the mirror.
\nThe parallel rays from the sun are focused on a very small area of the paper. If a concave mirror is used, the light rays will be converged in front of the mirror. Whereas, when rays are focused on a convex mirror, the light rays appear to come from the focal point behind the mirror. So, a concave mirror focuses the light rays more strongly on the paper piece, when compared to a convex mirror.
\nFor best results, the paper should be held at the focal length of the concave mirror, such that, the light rays converge on the small area of the paper and the heating would be the greatest.<\/p>\nChapter 26 Geometrical Optics Q.5P<\/strong>
\nSunlight enters a room at an angle of 32\u00b0 above the horizontal and reflects from a small mirror lying flat on the floor. The reflected light forms a spot on a wall that is 2.0 m behind the mirror, as shown in Figure If you now place a pencil under the
\n
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.6CQ<\/strong>
\nWhen light propagates from one medium to another, does it always bend toward the normal? Explain.
\nSolution:<\/strong><\/span>
\nNo, the bending of light depends upon the speed of the medium.
\nThe light bends towards the normal when the light enters a medium in which its speed of propagation is less than it was in the first medium.
\nThe light bends away from the normal when the light enters a medium in which its speed of propagation is greater than the first medium.<\/p>\nChapter 26 Geometrical Optics Q.6P<\/strong>
\nYou stand 1.50 m m front of a wall and gaze downward at a small vertical mirror mounted on it. In this mirror you can see the reflection of your shoes. If your eyes are 1.85 m above your feet, through what angle should the mirror be tilted for you to see your eyes reflected in the mirror? (The location of the mirror remains the same, only its angle to the vertical is changed.)
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.7CQ<\/strong>
\nA swimmer at point B in Figure needs help. Two lifeguards depart simultaneously from their tower at point A, but they follow different paths. Although both lifeguards run with equal speed on the sand and swim with equal speed in the water, the lifeguard who follows the longer path, ACB, arrives at point B before the lifeguard who follows the shorter, straight-line path from A to B. Explain.
\n
\nSolution:<\/strong><\/span>
\nOne can run on sand with speed more than the speed with which one swim in water.
\nSince the lifeguard who follows the path ACB run more distance on sand compared to other, hence that lifeguard takes less time to travel more distance.
\nDistance travelled in water by lifeguard of path ACB is less than other, hence it takes less time to reach at same point B while speed of both lifeguards are same.<\/p>\nChapter 26 Geometrical Optics Q.7P<\/strong>
\nIP Standing 2.3 m in front of a small vertical mirror, you see the reflection of your belt buckle, which is 0.72 m below your eyes. (a) What is the vertical location of the mirror relative to the level of your eyes? (b) What angle do your eyes make with the horizontal when you look at the buckle? (c) If you now move backward until you are 6.0 m from the mirror, will you still see the buckle, or will you see a point on your body that is above or below the buckle? Explain.
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.8CQ<\/strong>
\nWhen you observe a mirage on a hot day, what are you actually seeing when you gaze at the \u201cpool of water\u201d in the distance?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.8P<\/strong>
\nHow many times does the light beam shown in Figure reflect from (a) the top and (b) the bottom mirror?
\n
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.9CQ<\/strong>
\nExplain the difference between a virtual and a real image.
\nSolution:<\/strong><\/span>
\nThe main difference between real image and virtual image is
\n(i) Real image:\u2013 If a divergent beam of light from a point after reflection or refraction actually converges to a second point, then the second point is called the real image of first point. The real image can be caught on a screen.
\n(ii) Virtual Image:\u2013 If a divergent beam of light from a point , after reflection or refraction , appears to diverge from a second point, then the second point is called the virtual image of the first point. The virtual image cannot be caught on a screen. The virtual image can be photographed.<\/p>\nChapter 26 Geometrical Optics Q.9P<\/strong>
\nCE If you view a clock in a mirror, do the hands rotate clockwise or counterclockwise?
\n
\nSolution:<\/strong><\/span>
\nFrom the figure we can say that, the hands on mirror \u2013 image clock rotate counter clock wise<\/p>\nChapter 26 Geometrical Optics Q.10CQ<\/strong>
\nSitting on a deserted beach one evening, you watch as the last bit of the Sun approaches the horizon. Just before the Sun disappears from sight, is the top of the Sim actually above or below the horizon? That is, if Earth\u2019s atmosphere could be instantly removed just before the Sun disappeared, would the Sun still be visible, or would it be below the horizon? Explain.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.10P<\/strong>
\nA 12.5-foot-long, nearsighted python is stretched out perpendicular to a plane mirror, admiring its reflected image. If the greatest distance to which the snake can see cleariy is 26.0 ft, how close must its head be to the mirror for it to see a clear image of its tail?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.11CQ<\/strong>
\nA large, empty coffee mug sits on a table. From your vantage point the bottom of the mug is not visible. When the mug is filled with wa ter, however, you can see the bottom of the mug. Explain.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.11P<\/strong>
\n(a) How rapidly does the distance between you and your mirror image decrease if you walk directly toward a mirror with a speed of 2.6 m\/s? (b) Repeat part (a) for the case in which you walk toward a mirror but at an angle of 38\u00b0 to its normal.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.12CQ<\/strong>
\nThe Disappearing Eyedropper The accompanying photograph shows eyedroppers partially immersed in oil (left) and water (right). Explain why the dropper is invisible in the oil.
\n
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.12P<\/strong>
\nYou are 1.9 m tall and stand 3.2 m from a plane mirror that extends vertically upward from the floor. On the floor 1.5 m in front of the mirror is a small table, 0.80 m high. What is the minimum height the mirror must have for you to be able to see the top of the table in the mirror?
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.13CQ<\/strong>
\nThe Invisible Man In the H. G. Wells novel The Invisible Man, a person becomes invisible by altering his index of refraction to match that of air. This is the idea behind the disappearing eye-dropper in Conceptual Question. If the invisible man could actually do this, would he be able to see? Explain.
\nQuestion
\n12. The Disappearing Eyedropper The accompanying photograph shows eyedroppers partially immersed in oil (left) and water (right). Explain why the dropper is invisible in the oil.
\n
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.13P<\/strong>
\nThe rear window in a car is approximately a rectangle, 1.3 m wide and 0.30 m high. The inside rearview mirror is 0.50 m from the driver\u2019s eyes, and 1.50 m from the rear window. What are the minimum dimensions for the rearview mirror if the driver is to be able to see the entire width and height of the rear window in the mirror without moving her head?
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.14CQ<\/strong>
\nWhat\u2019s the Secret? The top of Figure shows the words SECRET CODE written in different colors. If you place a cylindrical rod of glass or plastic just above the words, you find that SECRET appears inverted, but CODE does not Explain.
\n
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.14P<\/strong>
\nIP You hold a small plane mirror 0.50 m in front of your eyes, as shown in Figure (not to scale). The mirror is 0.32 cm high, and in it you see the image of a tall building behind you. (a) If the building is 95 m behind you, what vertical height of the building, H,can be seen in the mirror at any one time? (b) If you move the mirror closer to your eyes, does your answer to part (a) increase, decrease, or stay the same? Explain.
\n
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.15P<\/strong>
\nTwo rays of light converge toward each other, as sljown in Figure forming an angle of 27\u00b0. Before they intersect, however, they are reflected from a circular plane mirror with a diameter of 11 cm. If the mirror can be moved horizontally to
\n
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.16P<\/strong>
\nFor a corner reflector to be effective, its surfaces must be pre cisely perpendicular. Suppose the surfaces of a comer reflector left on the Moon\u2019s surface by the Apollo astronauts formed a 90.001\u00b0 angle with each other. If a laser beam is bounced back to Earth from this reflector, how far (in kilometers) from its starting point will the reflected beam strike Earth? For simplicity, assume the beam reflects h-om only two sides of the reflector, and that it strikes the first surface at precisely 45\u00b0.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.17P<\/strong>
\nCE Astronomers often use large mirrors in their telescopes to gather as much light as possible from faint distant objects. Should the mirror in their telescopes be concave or convex? Explain.
\nSolution:<\/strong><\/span>
\nThe mirrors used by the Astronomers in their telescopes are always concave, because concave mirrors focus all parallel rays of light (as from the stars) to a point in front of the mirror. On the other hand convex mirror disperse parallel rays of light by sending them outward on divergent paths.<\/p>\nChapter 26 Geometrical Optics Q.18P<\/strong>
\nA section of a sphere has a radius of curvature of 0.86 m. If this section is painted with a reflective coating on both sides, what is the focal length of (a) the convex side and (b) the concave side?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.19P<\/strong>
\nAmirrored-giass gazing globe in a garden is 31.9 cm in diameter. What is the focal length of the globe?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.20P<\/strong>
\nSunlight reflects from a concave piece of broken glass, converging to a point 15 cm from the glass. What is the radius of curvature of the glass?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.21P<\/strong>
\nCE You hold a shiny tablespoon at arm\u2019s length and look at the back side of the spoon. (a) Is the image you see of yourself upright or inverted? (b) Is the image enlarged or reduced? (c) Is the image real or virtual?
\nSolution:<\/strong><\/span>
\nHere the back of the spoon behaves like a convex mirror. Therefore from the conditions of the convex mirror we can say that the image is
\na) Upright
\nb) The image is reduced in size.
\nc) Behind the spoon no light passes through it. So, the image is a virtual image.<\/p>\nChapter 26 Geometrical Optics Q.22P<\/strong>
\nCE You hold a shiny tablespoon at arm\u2019s length and look at the front side of the spoon. (a) Is the image you see of yourself upright or inverted? (b) Is the image enlarged or reduced? (c) Is the image real or virtual?
\nSolution:<\/strong><\/span>
\nDue to the silver coating, the spoon acts as a mirror and the front side of the spoon means we are looking at a concave mirror. In addition, holding the spoon at arms length means that we are outside the focal point of the mirror \u2013 clearly the focal length of the front side of a spoon is only a few centimeters.
\nIf follows that our image is reduced, real and inverted.<\/p>\nChapter 26 Geometrical Optics Q.23P<\/strong>
\nCE An object is placed in front of a convex mirror whose radius of curvature is R. What is the greatest distance behind the mirror that the image can be formed?
\nSolution:<\/strong><\/span>
\nWe know that if the object is in front of the mirror then image produced by a convex mirror will be always behind the mirror. The greatest image distance occurs when the object is infinitely far from the mirror. In the case when the image is at the focal point, the greatest distance the image can be behind the mirror is \\( f\\quad =\\cfrac { R }{ 2 } \\)<\/p>\nChapter 26 Geometrical Optics Q.24P<\/strong>
\nCE An object is placed to the left of a concave mirror, beyond its focal point. In which direction will the image move when the object is moved farther to the left?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.25P<\/strong>
\nCE An object is placed to the left of a convex mirror. In which direction will the image move when the object is moved farther to the left?
\nSolution:<\/strong><\/span>
\n
\nWe know that the image produced by a convex mirror is always behind mirror.
\nWhen the object is moved farther to the left, the image will move to right, i.e., towards the focal point of the lens.<\/p>\nChapter 26 Geometrical Optics Q.26P<\/strong>
\nA small object is located 30.0 cm in frontofa concave mirror with a radius of curvature of 40.0 cm, Where will the image be formed?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.27P<\/strong>
\nUse ray diagrams to show whether the image formed by a convex mirror increases or decreases in size as an object is brought closer to the mirror\u2019s surface.
\nSolution:<\/strong><\/span>
\n
\nFrom the ray diagrams we can observe that there is an increase in size of the image if the object is brought closer to the mirror surface.<\/p>\nChapter 26 Geometrical Optics Q.28P<\/strong>
\nAn object with a height of 46 cm is placed 2.4 m in front of a concave mirror with a focal length of 0.50 m. (a) Determine the approximate location and size of the image using a ray diagram. (b) Is the image upright or inverted?
\nSolution:<\/strong><\/span>
\n
\n
\n(b) The image formed just before the concave mirror and the image is inverted.<\/p>\nChapter 26 Geometrical Optics Q.29P<\/strong>
\nFind the location and magnification of the image produced by the mirror in Problem using the mirror and magnification equations.
\nProblem
\n28. An object with a height of 46 cm is placed 2.4 m in front of a concave mirror with a focal length of 0.50 m. (a) Determine the approximate location and size of the image using a ray diagram. (b) Is the image upright or inverted?
\nSolution:<\/strong><\/span>
\n
\n\u2234 Image is formed at 0.63 m with a magnification -0.26<\/p>\nChapter 26 Geometrical Optics Q.30P<\/strong>
\nAn object with a height of 46 cm is placed 2.4 m in front of a convex mirror with a focal length of \u22120.50 m. (a) Determine the approximate location and size of the image using a ray diagram. (b) Is the image upright or inverted?
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.31P<\/strong>
\nFind the loca ti on and magnification of Ehe image produced by the mirror in Problem using the mirror and magnification equations.
\nProblem
\n30. An object with a height of 46 cm is placed 2.4 m in front of a convex mirror with a focal length of \u22120.50 m. (a) Determine the approximate location and size of the image using a ray diagram. (b) Is the image upright or inverted?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.32P<\/strong>
\nDuring a daytime football game you notice that a player\u2019s reflective helmet forms an image of the Sun 4.8 cm behind the surface of the helmet. What is the radius of curvature of the helmet, assuming it to be roughly spherical?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.33P<\/strong>
\nIP A magician wishes to create the illusion of a 2.74-m-tall elephant. He plans to do this by forming a virtual image of a 50.0-cm-tall model elephant with the help of a spherical mirror. (a) Should the mirror be concave or convex? (b) If the model must be placed 3.00 m from the mirror, what radius of curvature is needed? (c) How far from the mirror will the image be formed?
\nSolution:<\/strong><\/span>
\n
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.34P<\/strong>
\nA person 1.7 m tall stands 0.66 m from a reflecting globe in a garden. (a) If the diameter of the globe is 18 cm, where is the image of the person, relative to the surface of the globe? (b) How large is the person\u2019s image?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.35P<\/strong>
\nShaving \/makeup mirrors typically have one flat and one concave (magnifying) surface. You find that you can project a magnified image of a lightbulb onto the wall of your bathroom if you hold the mirror 1.8 m from the bulb and 3.5 m from the wall. (a) What is the magnification of the image? (b) Is the image erect or inverted? (c) What is the focal length of the mirror?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.36P<\/strong>
\nThe Hale Telescope The 200-inch-diameter concave mirror of the Hale telescope on Mount Falomar has a focal length of 16.9 m. An astronomer stands 20.0 m in front of this mirror. (a) Where is her image located? is it in front of or behind the mirror? (b) Is her image real or virtual? How do you know? (c) What is the magnification of her image?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.37P<\/strong>
\nA concave mirror produces a virtual image that is three times as tall as the object. (a) If the object is 28 cm in front of the mirror, what is the image distance? (b) What is the focal length of this mirror?
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.38P<\/strong>
\nA concave mirror produces a real image that is three times as large as the object. (a) If the object is 22 cm in front of the mirror, what is the image distance? (b) What is the focal length of this mirror?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.39P<\/strong>
\nThe virtual image produced by a convex mirror is one-quarter the size of the object. (a) If the object is 36 cm in front of the mirror, what is the image distance? (b) What is the focal length of this mirror?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.40P<\/strong>
\nIP A 5.7-ft tallshopper in a department store is 17 ft from a convex security mirror. The shopper notices that his image in the mirror appears to be only 6.4 in. tali. (a) Ts the shopper\u2019s image upright or inverted? Explain. (b) What is the mirror\u2019s radius of curvature?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.41P<\/strong>
\nYou view a nearby tree in a concave mirror. The inverted image of the tree is 3.8 cm high and is located 7.0 cm in front of the mirror. If the tree is 23 m from the mirror, what is its height?
\nSolution:<\/strong><\/span>
\n
\n<\/p>\nChapter 26 Geometrical Optics Q.42P<\/strong>
\nA shaving\/makeup mirror produces an erect image that is magnified by a factor of2.2 when your face is 25 cm from the mirror. What is the mirror\u2019s radius of curvature?
\nSolution:<\/strong><\/span>
\n1403-26-42P SA Code: 6078.SRCode: 5784
\n<\/p>\nChapter 26 Geometrical Optics Q.43P<\/strong>
\nA concave mirror with a focal length of 36 cm produces an image whose distance from the mirror is one-third the object distance. Find the object and image distances.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.44P<\/strong>
\nCE Predict\/Explain When a ray of light enters a glass lens surrounded by air, it slows down. (a) As it leaves the glass, does its speed increase, decrease, or stay the same? (b) Choose the best explanation from among the following:
\nI. Its speed increases because the ray is now propagating in a medium with a smaller index of refraction.
\nII. The speed decreases because the speed of light decreases whenever light moves from one medium to another.
\nIII. The speed will stay the same because the speed of light is a universal constant.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.45P<\/strong>
\nCE Samurai Fishing A humorous scene in Akira Kurosawa\u2019s classic film The Seven Samumi shows the young samurai Kikuchiyo wading into a small stream and plucking a fish from it for his dinner. (a) As Kikuchiyo looks through the water to the fish, does he sec it in the general direction of point 1or point 2 in Figure? (b) If the fish looks up at Kikuchiyo, does it see Kikuchiyo\u2019s head in the general direction of point 3 or point 4?
\n
\nSolution:<\/strong><\/span>
\n
\n(b)
\nIf the ray from the fish toward the head is extended without any bending, then the fish sees the head along the direction of point 4.
\nTherefore the right answer is point 4.<\/p>\nChapter 26 Geometrical Optics Q.46P<\/strong>
\nCE When color A and color B are sent through a prism, color Ais bent more than color B. Which color travels more rapidly in the prism? Explain.
\nSolution:<\/strong><\/span>
\nThe speed of light in a material is given by \\( \\frac { c }{ n } \\) The color with the smaller reflective index has the greater speed, so from the given data we can say that the color B travels more rapidly because the color B has bent less than the color A.<\/p>\nChapter 26 Geometrical Optics Q.47P<\/strong>
\nCE Day Versus Night (a) Imagine for a moment that the Earth has no atmosphere. Over the period of a year, is the number of daylight hours at your home greater than, less than, or equal to the number of nighttime hours? (b) Repeat part (a), only this time take into account the Earth\u2019s atmosphere.
\nSolution:<\/strong><\/span>
\na) The atmosphere acts as a spherical mirror by reflecting sunlight. If there is no atmosphere, Sunlight is trapped within the atmosphere due to the reflecting effects of gases. Therefore, day and night is depends upon whether the sun is shining on the planet or not. Since the Earth rotates about its axis with constant speed and resolves around the sun, half of the earth faces the sun at any given time. Thus there should be an equal number of day light times and night time hours.
\nb) If the atmosphere is present, some of the light is absorbed by the atmosphere of the earth. The light gets refracting during dawn and dusk adding to daylight hours and reducing night time hours, so daylight hours are greater than night time.<\/p>\nChapter 26 Geometrical Optics Q.48P<\/strong>
\nCE Predict\/Explain A kitchen has twin side-by-side sinks. One sink is filled with water, the other is empty. (a) Does the sink with water appear to be deeper, shallower, or the same depth as the empty sink? (b) Choose the best explanation from among the following:
\nI. The sink with water appears deeper because you have to look through the water to sec the bottom.
\nII. Water bends the light, making an object under the water appear to be closer to the surface. Thus the water-filled sink appears shallower.
\nIII. The sinks are identical, and therefore have the same depth. This doesn\u2019t change by putting water in one of them.
\nSolution:<\/strong><\/span>
\n<\/p>\nChapter 26 Geometrical Optics Q.49P<\/strong>