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प्रश्न
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of astronomical telescope.
उत्तर
Object is at infinity.
Image is formed at F2 on the other side of lens. Image is real; inverted and almost diminished to a point.
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संबंधित प्रश्न
"A convex lens can form a magnified erect as well as magnified inverted image of an object placed in front of it." Draw ray diagram to justify this statement stating the position of the object with respect to the lens in each case.
If you focus the image of a distant object, whose shape is given below, on a screen using a convex lens, the shape of the image of this object on the screen would be:
(a)
(b)
(c)
(d)
Which type of lenses are:
thicker in the middle than at the edges?
Complete the following sentence.
A long-sighted person cannot see ........... objects clearly. Long-sightedness can be corrected by using .............. lenses.
Draw a diagram to represent the second focus of a convex lens.
The given below figure shows an object OA and its image IB formed by a lens. State three characteristics of the image.
Analyse the following observation table showing variation of image-distance (v) with object-distance (u) in case of a convex lens and answer the questions that follow without doing any calculations:
| S. No. | Object-Distance u (cm) |
Image-Distance v (cm) |
| 1 | –60 | +12 |
| 2 | –30 | +15 |
| 3 | –20 | +20 |
| 4 | –15 | +30 |
| 5 | –12 | +60 |
| 6 | –9 | +90 |
(a) What is the focal length of the convex lens? State reason for your answer.
(b) For what object-distance (u) is the corresponding image-distance (v) not correct? How did you arrive at this conclusion?
(c) Choose an appropriate scale to draw a ray diagram for the observation at S. No. 4 and find the approximate value of magnification.
State the position of object, position of image, nature of image when: Convex lens is used as in searchlight.
Simple microscope : Number of convex lens one : : compound microscope : _______
Distinguish between Concave lens and Convex Lens.
