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प्रश्न
The image obtained while finding the focal length of convex lens is ....................
पर्याय
a) a real and erect.
b) virtual and erect.
c) real and inverted.
d) virtual and inverted.
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उत्तर
c) real and inverted.
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संबंधित प्रश्न
To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always
(a) erect and laterally inverted
(b) erect and diminished
(c) inverted and diminished
(d) virtual, inverted and diminished
To find the image-distance for varying object-distances in case of a convex lens, a student obtains on a screen a sharp image of a bright object placed very far from the lens. After that he gradually moves the object towards the lens and each time focuses its image of the screen.
(a) In which direction – towards or away from the lens, does he move the screen to focus the object?
(b) What happens to the size of image – does it increase or decrease?
(c) What happen when he moves the object very close to the lens?
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
Complete the following table:
| Instrument | Number of Convex Lenses |
Use |
| Simple Microscope | .............. | .............. |
| Compound Microscope | .............. | .............. |
| Telescope | .............. | .............. |
You eye contains a convex lens. Why is it unwise to look at the sun?
State whether the convex lens has a real focus or a virtual focus.
In order to obtain a real image twice the size of the object with a convex lens of focal length 15 cm, the object distance should be:
(a) more than 5 cm but less than 10 cm
(b) more than 10 cm but less than 15 cm
(c) more than 15 cm but less than 30 cm
(d) more than 30 cm but less than 60 cm
Which type of lenses are:
thicker in the middle than at the edges?
How would a pencil look like if you saw it through a convex lens? (Assume the pencil is close to the lens). Is the image real or virtual?
Where is the image formed?
A convex lens forms an image of an object equal to the size of the object. State two more characteristics of the image.
A lens forms an inverted image of an object. Name the kind of lens.
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.
Answer the following question.
List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining an image of a distant object on a screen.
Out of the two lenses one concave and the other convex state which is a convergent or a divergent type of a lens. Give a reason for your answer.
Write scientific reason.
Adults need bifocal lens spectacle.
A beam of light is incident through the holes on side A and emerges out of the holes on the other face of the box as show in the figure. Which of the following could be inside the box?
Which of the following statements is true?
Distinguish between Concave lens and Convex Lens.
