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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 real image cannot be obtained on a screen.
State two differences between a convex and a concave lens.
Which type of lens forms always a virtual image?
A diverging mirror of radius of curvature 40 cm forms an image which is half the height of the object. Find the object and image positions.
Explain why, a stick half immersed in water appears to be bent at the surface. Draw a labelled diagram to illustrate your answer.
Write the new Cartesian sign convention for spherical lenses.
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
What are the three principal rays that are drawn to construct the ray diagram for the image formed by a lens? Draw diagrams to support your answer.
A convex lens forms an image of an object equal to the size of the object. Where is the object placed in front of the lens?
Complete the ray diagram to show how the rays pass into and out of the lens?
