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प्रश्न
A man stands 10 m in front of a large plane mirror. How far must the walk before he is 5 m away from his image?
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उत्तर
Man should walk 7.5 m towards the mirror.
The reason being, the image formed by a plane mirror is the same distance behind the mirror as it is between the object and the mirror. A distance of 5m between man and his image means that the distance between him and the mirror = `52`= 2.5 m.
Thus, the distance he should walk = 10 - 2.5 = 7.5 m.
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संबंधित प्रश्न
What is refraction of light?
State whether the following statement is true of false:
A student says that we can see an object because light from our eyes is reflected back by the object.
A wall reflects light and a mirror also reflects light. What difference is three in the way they reflect light?
With the help of a labelled ray-diagram, describe how a plane mirror forms an image of a point source of light placed in front of it. State the characteristics of the image formed in a plane mirror.
State two effects caused by the refraction of light.
Fill in the following blank with suitable word:
Light bends when is passes from water into air. We say that it is ............
What is meant by the 'angle of incidence' and the 'angle of refraction' for a ray of light?
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
How does the light have to enter the glass:
to produce a large amount of bending?
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
Draw a diagram showing the refraction of a light ray from water to glass. Label on it the incident ray, the angle of incidence (/), and the angle of refraction (r)
Draw suitable diagrams to illustrate how a beam of light incident parallel to the principal axis is reflected by:
(a) a concave mirror, and (b) a convex mirror
A ray of light A incident from air suffers partial reflection and refraction at the boundary of water.
- Complete the diagram showing (i) the reflected ray B and (ii) the refracted ray C.
- How are the angles of incidence i and refraction r related?
Define the principal focus of a concave mirror.
A real image is formed by the light rays after reflection or refraction when they:
- actually meet or intersect with each other.
- actually converge at a point.
- appear to meet when they are produced in the backward direction.
- appear to diverge from a point.
Which of the above statements are correct?
Observe the given figure and name the following.
| Ray AB | |
| Ray NM | |
| Ray MD | |
| ∠ r |
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
