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प्रश्न
Only one of the following applies to a concave lens. This is:
(a) focal length is positive
(b) image distance can be positive or negative
(c) height of image can be positive or negative
(d) image distance is always negative
उत्तर
image distance is always negative
Because a concave lens always forms a virtual image on the left side of the lens.
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संबंधित प्रश्न
Due to gradual weakening of ciliary muscles and diminishing flexibility of the eye lens a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve the vision. Explain the structure and function of such a lens.
Where must the object be placed for the image formed by a converging lens to be:
virtual, upright and larger than the object?
An illuminated object is placed at a distance of 20 cm from a converging lens of focal length 15 cm. The image obtained on the screen is:
(a) upright and magnified
(b) inverted and magnified
(c) inverted and diminished
(d) upright and diminished
Which type of lens is
a diverging lens? Explain your answer with diagrams.
A concave lens of 20 cm focal length forms an image 15 cm from the lens. Compute the object distance.
A student obtained clear image of window grills on the screen. But the teacher told him to get the image of a tree far away, instead of window. To get a clear image, the lens must be ............................
A virtual diminished image is formed when an object is placed between the optical centre and the principal focus of a lens.
(i) Name the type of lens which forms the above image.
(ii) Draw a ray diagram to show the formation of the image with the above stated characteristics.
Draw neat diagram to show the
Divergent action of concave lens
Distinguish between concave and convex lens.
Convex lens : converging : : concave lens : _______
