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प्रश्न
_______ times larger images can be obtained by using a simple microscope.
विकल्प
5
10
20
60
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उत्तर
20 times larger images can be obtained by using a simple microscope.
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संबंधित प्रश्न
An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
A beam of light travelling in air is incident of water. Draw a ray-diagram indicating the change in its path in water.
Where should an object be placed in front of a convex lens so as to obtain its virtual, erect and magnified image?
Fill in the following blank with suitable word:
The image in a convex lens depends upon the distance of the ........... from the lens.
Define principal axis, principal focus and focal length of a convex lens.
Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).
Name one simple optical instrument in which the above arrangement of convex lens is used.
A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:
(a) 8 cm
(b) 16 cm
(c) 24 cm
(d) 32 cm
Calculate the focal length of a convex lens which produces a virtual image at a distance of 50 cm of an object placed 20 cm in front of it.
What type of images can a convex lens make?
Define the term principal axis of a lens.
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?
While determining the focal length of a convex lens, you try to focus the image of a distant object formed by the lens on the screen. The image formed on the screen, as compared to the object, should be
(A) erect and highly diminished
(B) erect and enlarged
(C) inverted and enlarged
(D) inverted and highly diminished
A student focussed the image of a distant object using a device ‘X’ on a white screen ‘S’ as shown in the figure. If the distance of the screen from the device is 40 cm, select the correct statement about the device.
(A) The device X is a convex lens of focal length 20 cm.
(B) The device X is a concave mirror of focal length 40 cm.
(C) The device X is a convex mirror of radius of curvature 40 cm.
(D) The device X is a convex lens of focal length 40 cm.
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
Write the name.
The lens used in simple microscope.
Observe the given figure and answer the following questions.
- Where is the above type of lens construction used?
- What type of image is formed by an objective lens?
- What happens instead of placing at Fo if the object is placed in between O and Fo?
Distinguish between:
Concave lens and Convex Lens
