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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
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.
An object is placed at a distance of 15 cm from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the 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.
Draw a labelled ray diagram to show how a ray of light passes through a parallel-sided glass block if it hits the glass block at an angle other than 90° (that is, obliquely to the glass block).
State any two uses of convex lenses.
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.
An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image?
(a) real, larger than the object
(b) erect, smaller than the object
(c) inverted, same size as object
(d) virtual, larger than the object
Describe the nature of image formed when an object is placed at a distance of 30 cm from a convex lens of focal length 15 cm.
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?
In figure , name the ray which represents the correct path of light while emerging out through
a glass block.
The diagrams (a) and (b) in Figure below show the refraction of a monochromatic ray of light through a parallel sided glass block and a prism respectively. In each diagram, label the incident, refracted emergent rays and the angle of deviation.
Study the diagram below.
what are the points O, O’ called?
When you focus the image of a distant flag, whose shape is given below, on a screen using a convex lens, the shape of the image as it appears on the screen is
(A)
(B)
(C)
(D)
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
Yesh find out F1 and F2 of symmetric convex lens experimentally then which conclusion is true.
A concave mirror and convex lens are held in water. What changes, if any, do you expect in their focal length?
Where should an object be placed in front of a convex lens so as to form an inverted and enlarged image? Will the image be real or virtual? Draw a ray diagram to illustrate your answer.
Distinguish between:
Concave lens and Convex Lens
