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प्रश्न
The distance between principal focus and optical centre of the lens is _________.
- diameter
- focal length
- principal axis
- optical centre
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उत्तर
(b) Focal length
The distance between the principal focus and the optical centre of the lens is its focal length.
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संबंधित प्रश्न
Define focal length of a divergent lens.
An image formed by a concave ______ cannot be obtained on a screen.
A concave lens always forms a virtual image.
A real image cannot be obtained on a screen.
State two differences between a convex and a concave lens.
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Explain why, a stick half immersed in water appears to be bent at the surface. Draw a labelled diagram to illustrate your answer.
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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
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My grandfather uses a bifocal lens in his spectacle. Explain why.
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 |
