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प्रश्न
: Object near the lens : : ______ : 
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उत्तर
: Object near the lens : : Object at focus :
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संबंधित प्रश्न
A student is using a convex lens of focal length 18 cm to study the image formation by it for the various positions of the object. He observes that when he places the object at 27 cm, the location of the image is at 54 cm on the other side of the lens. Identify from the following diagram the three rays that are obeying the laws of refraction and may be used to draw the corresponding ray diagram.
(A) 1, 2 and 4
(B) 1, 3 and 5
(C) 2, 4 and 5
(D) 2, 3 and 4
Draw a ray diagram to show the formation of image in the above situation
Study the given ray diagrams and select the correct statement from the following:
(A) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20 cm and 25 cm respectively.
(B) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 10 cm and 25 cm respectively.
(C) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm and 25 cm respectively.
(D) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.
Write one condition where it does not bend when entering a medium of different optical density.
Draw a ray diagram to show the formation of the image of an object be placed so that a real and inverted image of the same size as the object is obtained using a convex lens
Draw a labelled ray diagram to show how a ray of light is refracted when it passes:
from an optically denser medium into air.
The diagram given alongside shows a ray of light entering a rectangular block of glass.
(a) Copy the diagram and draw the normal at the point of entry.
(b) Draw the approximate path of the ray of light through the glass block and out of the other side.
Describe with the help of a ray-diagram, the formation of image of a finite object placed in front of convex lens between f and 2f. Give two characteristics of the image so formed.
Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
0.25 m
A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below:
Which of the following could be inside the box?
(a) a rectangular glass block
(b) a concave lens
(c) a convex lens
(d) a glass prism
Define the term principal axis of a lens.
A convex lens is placed in water. Its focal length will ______.
In the following cases, where must an object be placed in front of a convex lens so that the image formed is upright and enlarged?
List four properties of the image formed by a convex mirror.
Observe the following figure and answer the questions.
a) Which optical instrument shows arrangement of lenses as shown in the figure?
b) Write in brief the working of this optical instrument.
c) How can we get different magnifications in this optical instrument?
d) Draw the figure again and labelled it properly
Where must a point source of light be placed in front of a convex lens so as to obtain a parallel beam of light?
If an object is placed in front of a convex lens beyond 2F1, then what will be the position, relative size, and nature of an image which is formed? Explain with a ray diagram.
Convex lens is also known as ______.
Distinguish between:
Concave lens and Convex Lens
Distinguish between:
Concave lens and Convex lens
