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प्रश्न
Observe the following figure and complete the table:
| Points | Answer |
| (i) Position of the object | |
| (ii) Position of the image | |
| (iii) Size of the image | |
| (iv) Nature of the image |
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उत्तर
| Points | Answer |
| (i) Position of the object | between F1 and optical center |
| (ii) Position of the image | same side to the object (between 2F1 and F1) |
| (iii) Size of the image | Magnified |
| (iv) Nature of the image | Virtual and erect |
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संबंधित प्रश्न
A ray of light travelling in air is incident on a parallel-sided glass slab (or rectangular glass slab). Draw a ray-diagram indicating the change in its path in glass.
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:
Parallel rays of light are refracted by a convex lens to a point called the ........
State whether convex lens has a real focus or a virtual focus.
Find the position and nature of the image of an object 5 cm high and 10 cm in front of a convex lens of focal length 6 cm.
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 would be the image distance if the object distance was 90 cm?
How would a pencil look like if you saw it through How would a pencil look like if you saw it through
What kind of lens can form:
am erect diminished image?
A parallel oblique beam of light falls on a convex lens. Draw a diagram to show the refraction of light through the lens.
A convex lens forms an image of an object equal to the size of the object. Draw a diagram to illustrate it.
A convex lens has a divergent action and a concave lens has a convergent action.
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.
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
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.
State the nature and position of the object on the principal axis to obtain a real image of the same size
In the figure given below L is a convex lens, M is a plane mirror and S is a point source of light. Rays of light from the source S return to their point of origin. Complete the ray diagram to show this. What is the point S called?
_______ is a combination of two convex lenses with small focal length.
The above image shows a thin lens with a focal length of 5m.
- What is the kind of lens shown in the above figure?
- If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed.
- Draw a neatly labelled diagram of the image formation mentioned in (ii).
