Q1. Why does the warning “Objects in mirror are closer than they appear” appear on vehicle side mirrors?
Ans: Side mirrors in vehicles are usually convex mirrors. They make images smaller than the actual object size, so the objects seem farther away than they really are. The warning is to remind drivers about this illusion for safety.
Q2. How can you tell if a mirror is concave, convex, or plane just by looking at its image?
Ans: A concave mirror shows a large upright image when close and an inverted one when far. A convex mirror always shows a smaller upright image. A plane mirror always shows an upright image of the same size.
Q3. Why are convex mirrors useful at road intersections?
Ans: Convex mirrors give a wider field of view than plane mirrors. At intersections, they help drivers see vehicles coming from different directions, reducing the risk of accidents.
Q4. How are spherical mirrors shaped during manufacturing?
Ans: They start as flat glass pieces that are ground and polished into a curved shape. Then a thin reflective coating, like aluminum, is added to make them work as mirrors.
Q5. What happens if a beam of light strikes a mirror along the normal?
Ans: The light is reflected back along the same path. In this case, both the angle of incidence and reflection are zero.
Q6. How do laws of reflection apply to spherical mirrors?
Ans: The laws work for each ray of light, even if the mirror surface is curved. In concave mirrors, parallel rays converge, while in convex mirrors, parallel rays diverge, but each ray still obeys the reflection rules.
Laws of Reflection
Q7. Why is it dangerous to look at the Sun through a concave mirror?
Ans: A concave mirror focuses sunlight into a small spot. The intense light and heat can damage the eyes permanently.
Q8. Why does the size of an image change when the object distance changes for a convex lens?
Ans: Changing the object’s distance changes the point where light rays meet after passing through the lens. This changes whether the image is upright or inverted and also its size.
Q9. How can you differentiate a convex lens from a concave lens by just touching it?
Ans: A convex lens feels thicker in the middle and thinner at the edges. A concave lens feels thinner in the middle and thicker at the edges.
Q10. Why does a convex lens focus sunlight to a hot point?
Ans: A convex lens converges parallel rays from the Sun to a single spot. This concentrated light produces heat that can burn paper.
Q12. How does the human eye’s lens help us see both near and far objects?
Ans: The eye’s natural convex lens changes shape to adjust focus. It becomes thicker for near objects and thinner for far objects, so we can see both clearly.
Q. 2. What are the characteristics of image formed by plane mirror?
Ans. Characteristics of image formed by a plane mirror are:
(i) Plane mirror forms virtual images.
(ii) Plane mirror forms erect images.
(iii) Image is laterally inverted.
(iv) Image formed is of the same size as the object.
(v) The distance of image from the mirror is equal to the distance of object from the mirror.
Q. 3. How will you prove that the angle of incidence is equal to the angle of reflection.
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Q4. Explain how spherical mirrors are made and how the placement of the reflective coating determines the type of mirror.
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Q5. Describe in detail the differences in image formation between plane mirrors and spherical mirrors.
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Q6. How do concave and convex mirrors differently direct parallel rays of light? Explain why.
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Q7. Explain the role of the two laws of reflection when light strikes spherical mirrors.
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Q8. How can a concave mirror be used to demonstrate the focusing of sunlight, and why is it potentially dangerous?
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Q9. Explain why a water droplet can act as a simple lens, using the experiment described.
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Q10. How does the image formation in a convex lens change as the distance between the object and lens changes?
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Q11. Compare the effect of a convex lens and a concave lens on parallel beams of light.
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59 videos|235 docs|13 tests
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1. What are the different types of mirrors and how do they work? | ![]() |
2. How do lenses differ from mirrors in terms of image formation? | ![]() |
3. What is the law of reflection and how is it applied in real life? | ![]() |
4. What are the applications of concave and convex mirrors? | ![]() |
5. How does the focal length of a lens affect image formation? | ![]() |