1. In which of the following arrangements, X or Y will you see the candle? Justify your choice. X. This is because in Y, cardboard B is displaced. So, light cannot pass through the hole in B as Light always travels in a straight line. 2. If an object is placed at 0.5 m in front of a plane mirror, the distance between the object and the image formed by the mirror will be (a) 2 m (b) 1 m (c) 0.5 m (d) 0.25 m (b) Distance between object and mirror + distance between mirror and image = (0.5 + 0.5) m = 1 m 3. Ram is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be a) 3 m b) 5 m c) 6 m d) 8 m 4. A ball was initially kept in front of a plane mirror as shown. The same ball is then kept at different locations indicated. At which of the following locations, will you obtain the image of same size as formed when kept at initial position? a) Only P b) Only P and Q c) Only Q and R d) All the points The image of an object irrespective of its distance from a plane mirror will always be of same size as that of the object. 5. Observe the picture and answer. Due to which property of the plane mirror this happens? a) Optical illusion b) Reflection b) Lateral inversion d) Diffusion 6. A ray of light is incident on a plane mirror and the angle of reflection is 50 degrees. Calculate the angle between the incident ray and the reflected ray. Angle of reflection = 50° Angle of incidence= Angle of reflection = 50° The angle between incident ray and the reflected ray= 50° + 50°= 100° 7. Recall the type of images formed by plane mirrors and select the picture which correctly represents the object and image. Red arrows represent objects and blue represent images. Ans: Option A TOPIC: 15.4 -PLAYING WITH SPHERICAL MIRRORS 8. The image of a potted plant in a mirror is shown. Which type of mirror is it? a) Convex mirror b) Concave mirror c) Plane mirror d) All the above b) concave mirror The image of the object is enlarged and erect, so it must be kept in front of a concave mirror. 9. While driving the scooter, Ramesh met with an accident and the side mirror of the scooter broke. The mechanic replaced it with a plane mirror. Specify the inconvenience caused to the driver of the scooter. Convex mirror is used as rear-view mirror in vehicles. If it is replaced with a plane mirror, then driver of the scooter will not be able to see the traffic spread over a large area behind him. 10. A man standing in front of a special mirror finds his image having a very small head, a fat body and legs of normal size. What is the shape of: (a) top part of the mirror? (b) middle part of the mirror? (c) bottom part of the mirror? Give reasons for your choice. The shapes of the three parts of the special mirror are: (a) Convex mirror at the top as head size is diminished. A convex mirror forms a virtual, erect image which is smaller than the object. (b) Concave mirror in the middle as the body size is enlarged. Only a concave mirror can produce a virtual and enlarged image. (c) Plane mirror at the bottom as the size of legs are same. A plane mirror always forms a virtual image and size of the image is same size as the object. 11. A shopkeeper wanted to fix a mirror which would give a maximum view of his shop. What type of mirror should he use? Give reason. The shopkeeper should use convex mirror because it forms images of objects spread from large areas. 12. In the figure, a block is kept in front of a combination of mirrors such that an erect image can be seen. Which of the following is correct regarding the size of the image with respect to the block(object)? a) It will be larger in upper part and smaller in lower part b) It will be smaller in upper part and larger in lower part c) It will be larger throughout the length d) It will be smaller throughout the length e) It will be of same size as that of block Option a- (As the image formed is erect and upper portion is concave, it will form an enlarged image. As the lower portion is convex in shape, it will form diminished image.) 13. Case Study: A student is conducting an experiment using two different types of spherical mirrors. Mirror A and Mirror B are placed on separate tables, and the student uses the same object for both experiments, which is a small light bulb. When the light bulb is far from Mirror A, its image appears inverted, but when moved closer, the image becomes upright and bigger. In front of Mirror B, the image of the bulb always looks smaller than the actual bulb, no matter where it is placed. a) Identify the type of each mirror (Mirror A and Mirror B) based on the observations made by the student. b) If the student wants to use one of these mirrors for a makeup mirror, which one should be selected? Why? c) Suppose the student wants to focus sunlight into a small area to start a fire. Which mirror should be used and why? Answer: a) Mirror A: Concave mirror The image being inverted when the object is far, and upright & magnified when close indicates that Mirror A is a concave mirror. Concave mirrors produce different types of images depending on the object's distance from the mirror. Mirror B: Convex mirror The fact that the image is always smaller and upright suggests that Mirror B is a convex mirror. Convex mirrors always form virtual, diminished images, no matter the object's position. b) Mirror A (concave mirror) is ideal for a makeup mirror because when the object is placed near the mirror, it forms an upright and magnified image, making it easier to see finer details clearly. c)The student should use Mirror A, which is a concave mirror. Concave mirrors can focus parallel rays of light, such as sunlight, to a single point. This ability to concentrate light into a small area would generate enough heat at that focal point to start a fire. TOPIC: 15.5 - IMAGES FORMED BY LENSES 15.6 – SUNLIGHT-WHITE OR COLOURED? 15. The script shown on the right when seen with different lenses looks different as shown below. Identify the type of lens used in each case. A. In concave lens, the image formed is small and in convex lens, the image formed is large if it is erect and virtual. 16. You are provided with a concave mirror, a convex mirror, a concave lens and a convex lens. To obtain an enlarged image of an object, you can use either a) concave mirror or convex mirror. b) concave mirror or convex lens. c) concave mirror or concave lens. d) concave lens or convex lens. 17. The image formed by a lens is always virtual, erect and smaller in size for an object kept at different positions in front of it. Identify the nature of the lens. Concave lens 18. The distance between an object and a convex lens is changing. It is noticed that the size of the image formed on a screen is decreasing. Is the object moving in a direction towards the lens or away from it? The object is moving away from the lens. 19. The bottle shown in the figure is filled with water. If a light ray falls on the bottle as shown in the figure, then how will the ray emerge from the bottle? C- The bottle act as a diverging lens, so the emerging ray should come out as shown in option C. 20. Suppose we wish to obtain the real image of a distant tree. Explain two possible ways in which we can do it. Two possible ways in which the real image of a distant tree can be obtained are given below: a) By using a concave mirror and a screen- By using a concave mirror, a real image is formed if the object is at a distance from it. b) By using a convex lens and a screen- In a convex lens, when the object is far away from the lens, the image will be very close to the lens forming a real and inverted image. 21. It was observed that when the distance between an object and a lens decreases, the size of the image increases. a) What is the nature of this lens? b) If you keep on decreasing the distance between the object and the lens, will you still able to obtain the image on the screen? Explain. a) It is a convex lens. b) No, when the object is placed close to a convex lens, then the image formed is virtual, which cannot be obtained on the screen. 22. The path of light through lenses of two different types, represented by rectangular boxes A and B is as shown in the figure. What is the nature of lenses A and B? A. Convex lens B. Concave lens 23. a) Differentiate between the virtual images formed by convex and concave lens. b) Which lens can be used as a magnifying glass? Give reason. a) The virtual image formed by the convex lens is enlarged but the image formed by the concave lens is smaller than the object. b) A convex lens can be used as a magnifying glass because it produces a virtual, magnified image when the object is placed close to the lens, allowing for enlargement of small details. 24. Ann made light from a laser torch to fall on a prism. Will she be able to observe a band of seven colours? Explain with a reason. No, Ann cannot observe a band of colours because laser torch gives out light of a single colour.So she will observe only a single colour emerging from the prism.She cannot observe a spectrum of seven colours as in the case of white light. . 25. State the correct sequence (1-7) of colours in the spectrum formed by the prisms A and B, shown in the figure. Ans: 26. Case Study - Magnifying effect of water drop. While taking a walk in her garden, on an early winter morning, Swati noticed something interesting. The dew drops resting on the leaves made the part of the leaf look bigger than the surrounding region. She wondered how the drops were acting like a magnifying glass and decided to investigate this phenomenon by performing more experiments. Observe the picture Swati took to examine the magnifying effect of water drops. Which of the following factors are necessary for making the text appear bigger? A. Transparent nature of water B. The outwards curved surface of the water drop a. Both A and B b. Only A c. Only B Ans: Both A and B Research Project How do innovations in mirror and lens design contributed to advancements in imaging, telecommunications, and medical devices, and what are the specific technological improvements and applications in each of these fields?