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प्रश्न
i. Which type of microscope has the arrangement of lenses shown in the adjoining figure?
ii. Label the figure correctly.
iii. Write the working of this microscope.
iv. Where does this microscope used?
v. Suggest a way to increase the efficiency of this microscope.
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उत्तर
i. Compound microscope
ii. Scientifically and technically correct figure.
(Object, Objective lens, Eye piece, Image)
iii. Magnification is obtained by the combined effect of two
lenses. The magnification occurs in two stages. The image formed by the first lens acts as the object for the second lens. Clear image can be obtained by adjusting the distance between two lenses.
iv. To study small sized objects like blood cells, animal and plant
cells, bacteria.
v. Any relevant remedy (For example, Selection of lens with
appropriate focal length)
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संबंधित प्रश्न
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.
What type of lens would you use as a magnifying glass? How close must the object be to the lens?
Fill in the following blank with suitable word:
The image in a convex lens depends upon the distance of the ........... from the lens.
Explain with the help of a diagram, why the convex lens is also called a converging 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).
You eye contains a convex lens. Why is it unwise to look at the sun?
If the object is moved to a point only 3 cm away from the lens, what is the new position, height and nature of the image?
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
What is the focal length of this lens?
Define the term principal axis of a lens.
A convex lens is placed in water. Its focal length will ______.
A lens forms an upright and magnified image of an object. Name the lens.
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.
For finding the focal length of a convex lens by obtaining the image of a distant object, one should use as the object.
(1) a well lit distant tree
(2) window grill in the class room
(3) any distant tree
(4) a lighted candle kept at the other end of the table.
Where should an object be placed in front of a convex lens to get a real image of the size of the object?
An object 4.0 cm in size, is placed 25.0 cm in front of a concave mirror of focal length 15.0 cm.
- At what distance from the mirror should a screen be placed in order to obtain a sharp image?
- Find the size of the image.
- Draw a ray diagram to show the formation of the image in this case.
State the position of object, position of image, nature of image when: Convex lens is used as an erecting lens in terrestrial telescope.
Find the odd one out and give its explanation.
Differentiate convex lens and concave lens.
Distinguish between Concave lens and Convex Lens.
