The focal lengths of a thin convergent lens are 0.5m and 0.484m for red and blue rays, respectively. Find the chromatic aberration and dispersive power of the material of the lens.
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You given two planoconvex lenses of focal lengths `0.03`m and `0.05`m and asked to design an eye-piece free from chromatic aberration. Explain how you
Correct Answer - By keeping the lenses `0.04`m apart, `f_("equi")=0.0375`m, magnifying power = `7.67`, no
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Two convex lenses of focal lengths 2f and f are arranged to from an eye-piece and are spaced by f. The first lens is to be used as field lens and the
Correct Answer - (a) F = f, (b) positive, (c) free from spherical aberration but not chromatic, (d) eye-lens position falls as the focus of the field lens and so...
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The focal lengths of a thin convergent lens are 0.20m and 0.21m for voilet and red lights, respectively, An object is placed at a distance of 0.15m. C
Correct Answer - 0.075m
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An achromatic telescope objective of focal length 1.5m is consists of two thin lenses of dispersive power 0.050 and 0.075, respectively, placed in con
Correct Answer - For convex lens: `f=0.5m, omega=0.050` , for concave lens: `f=0.75m, omega=0.075`
2 Answers 1 views
Calculate the focal length of a convex lens of crown glass of dispersive power 0.012 and concave lens of dispersive power 0.020 that from an achromati
Correct Answer - `r_("common")=1.11 m,0.644m`
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How would you use two plano-convex lenses of focal lengths 6cm and 4cm to design an eye-piece free from chromatic aberration. What will be its focal l
Correct Answer - `4.8 cm, 5.2` negative
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Two parallel beams of light P and Q are incident normally on a prism and the transmitted rays are brought to focus with the help of a convergent lens
Correct Answer - [9I]
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A convergent lens with a focal length of f = 10 cm is cut into two halves that are then moved apart to a distance of d =0.5 mm (a double lens). Find t
Correct Answer - [0.1 mm]
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A concave lens is placed in the path of convergent rays. The rays are focussed on the axis 15 cm behind the lens. Where would these rays have been foc
Correct Answer - At a distance of 10 cm behind the lens
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Find the focal length and power of a convex lens, which when placed in contact with a concave lens of focal length `25 cm` forms a real image `5` time
Correct Answer - 10 cm, 10D
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