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प्रश्न
Suppose you have focused on a screen the image of candle flame placed at the farthest end of the laboratory table using a convex lens. If your teacher suggests you to focus the parallel rays of the sun, reaching your laboratory table, on the same screen, what you are expected to do is to move the:
(a) lens slightly towards the screen
(b) lens slightly away from the screen
(c) lens slightly towards the sun
(d) lens and screen both towards the sun
उत्तर
(a) lens slightly towards the screen
To focus the parallel rays of the Sun, the lens should be slightly moved towards the screen.
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संबंधित प्रश्न
A concave lens always forms a virtual image.
State two differences between a convex and a concave lens.
Which type of lens forms always a virtual image?
Explain why, a stick half immersed in water appears to be bent at the surface. Draw a labelled diagram to illustrate your answer.
Two lenses A and B have power of (i) +2D and (ii) −4D respectively. What is the nature and focal length of each lens?
If a spherical lens has a power of, −0.25 D, the focal length of this lens will be :
(a) −4 cm
(b) −400 mm
(c) −4 m
(d) −40 cm
If a spherical lens has a power of, −0.25 D, the focal length of this lens will be :
(a) −4 cm
(b) −400 mm
(c) −4 m
(d) −40 cm
Complete the ray diagram to show how the rays pass into and out of the lens?
Which diagram shows image formation of an object on a screen by a converging lens?
Complete the following table for convex lens:
| Sr. No. | Position of the object | Position of the image | Nature of the image |
| 1. | Beyond 2F1 | __________________ | ________________________ |
| 2. | __________________ | At infinity | ________________________ |
| 3. | __________________ | __________________ | Real, inverted and enlarged |
