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प्रश्न
Find the odd one out and give its explanation.
पर्याय
Eye piece
Magnifier
Kaleidoscope
Telescope
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उत्तर
Kaleidoscope
Explanation-
Kaleidoscope uses mirrors while other devices make use of lenses.
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संबंधित प्रश्न
A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen.
(a) In which direction-toward or away from the lens, does he move the screen to focus the image?
(b) How does the size of the image change?
(c) How does the intensity of the image change as the flame moves towards the lens?
(d) Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?
When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon occur?
An object is placed at a distance of 12 cm from a convex lens of focal length 8 cm. Find :
1) the position of the image
2) nature of the image
A 1 cm high object is placed at a distance of 2f from a convex lens. What is the height of the image formed?
Distinguish between a convex lens and concave lens. Which of the two is a converging lens : convex lens of concave lens?
State whether convex lens has a real focus or a virtual focus.
Calculate the focal length of a convex lens which produces a virtual image at a distance of 50 cm of an object placed 20 cm in front of it.
What kind of lens can form:
am erect diminished image?
Which causes more bending (or more refraction) of light rays passing through it : a convex lens of long focal length or a convex lens of short focal length?
In figure , name the ray which represents the correct path of light while emerging out through
a glass block.
A convex lens forms an image of an object equal to the size of the object. Draw a diagram to illustrate it.
A lens forms an upright and magnified image of an object. Name the lens.
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 objective lens of photographic camera.
Why do we say that the ‘2F’ and ‘F’ points of a convex lens can be regarded as a sort of ‘turning points’ as far as the nature of the image formed by it is concerned?
Diagram shows an object AB placed on the principal axis B of a convex lens placed in air. F1 and F2 are the two foci of the lens.
(i) Copy the diagram:
Draw a ray of light starting from B and passing through O. Show the same ray after refraction by the lens. Draw another ray from B which passes through F2 after refraction by the lens. Locate the final image
(ii) Is the image real or virtual?
Distinguish between:
Concave lens and Convex lens
Distinguish between Concave lens and Convex Lens.
