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प्रश्न
The sun is seen before the sunrise and after the sunset.
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उत्तर
EARLY SUNRISE and SUNSET: At sun Rise: When the Sun is just below the horizon, the light from the Sun suffers refraction from RARE to DENSER medium (As the atmosphere is warmer than layers near the earth at that time) bends towards the normal at each refraction. Due to continuous bending of light rays, the Sun can be seen even when its actual position is just below the Horizon. As a result, the Sun is seen in advance, two minutes before it rises above the horizon in the morning.
Similarly, in the evening Sun is seen delayed by 2 minutes longer above the horizon after the Sunset.
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संबंधित प्रश्न
A simple microscope is used by watch repairers. Give reason.
Match the items given in Column I with one or more items of Column II.
| Column I | Column II | ||
| (a) | A plane mirror | (i) | Used as a magnifying glass. |
| (b) | A convex mirror | (ii) | Can form image of objects spread over a large area. |
| (c) | A convex lens | (iii) | Used by dentists to see enlarged image of teeth. |
| (d) | A concave mirror | (iv) | The image is always inverted and magnified. |
| (e) | A concave lens | (v) | The image is erect and of the same size as the object. |
| (vi) | The image is erect and smaller in size than the object. |
Name the spherical mirror which can produce a real and diminished image of an object.
The diverging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the diverging lens in part (a).
Three mirrors are created from a single sphere. Which of the following - pole, centre of curvature, radius of curvature, principal axis - will be common to them and which will not be common?
State the two convenient rays that are chosen to construct the image by a spherical mirror for a given object? Explain your answer with the help of suitable ray diagrams.
An object 5 cm high is placed at a distance 60 cm in front of a concave mirror of focal length 10 cm. Find the position and size of the image.
Select the correct option:
Looking into a mirror one finds her image diminished, the mirror is:
Size of image of an object by a mirror having a focal length of 20 cm is observed to be reduced to 1/3rd of its size. At what distance the object has been placed from the mirror? What is the nature of the image and the mirror?
