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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
An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre 'O' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical 'O', principal focus F and height of the image on the diagram.
Where should an object be placed so that a real and inverted image of the same size as the object is obtained using a convex lens?
Where should an object be placed in front of a convex lens so as to obtain its virtual, erect and magnified image?
Describe with the help of a ray-diagram, the size, nature and position of the image formed by a convex lens when an object is placed beyond 2f in front of the lens.
How could you find the focal length of a convex lens rapidly but approximately?
A convex lens produces an inverted image magnified three times of an object placed at a distance of 15 cm from it. Calculate the focal length of the lens.
Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
0.25 m
What type of images can a convex lens make?
What kind of lens can form:
am erect diminished image?
The diagram alongside shows the refraction of a ray of light from sir to a liquid.
(a) write the values of (i) angle of incidence, (ii) angle of refraction.
(b) use snell’s law to find the refractive index of liquid with respect to air.
A parallel oblique beam of light falls on a convex lens. Draw a diagram to show the refraction of light through the lens.
A lens forms an upright and magnified image of an object State whether the image is real or virtual
To find the image distance for varying object distances in case of a convex lens of focal length 15 cm, a student obtains on a screen a sharp image of a bright object by placing it at 20 cm distance from the lens. After that he gradually moves the object away from the lens and each time focuses the image on the screen.
(a) In which direction-towards or away from the lens does he move the screen to focus the object?
(b) How does the size of image change?
(c) Approximately at what distance does he obtain the image of magnification –1?
(d) How does the intensity of image change as the object moves farther and farther away from the lens?
List four properties of the image formed by a convex mirror.
For finding the focal length of a convex lens by obtaining the image of a distant object, one should use as the object.
(1) a well lit distant tree
(2) window grill in the class room
(3) any distant tree
(4) a lighted candle kept at the other end of the table.
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 |
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of photographic camera.
Where should an object be placed in front of a convex lens so as to form an inverted and enlarged image? Will the image be real or virtual? Draw a ray diagram to illustrate your answer.
_______ is a combination of two convex lenses with small focal length.
Distinguish between:
Concave lens and Convex lens
