The dispersive powers of glasses of lenses used in an achromatic pair – McqOptions

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1.	The dispersive powers of glasses of lenses used in an achromatic pair are in the ratio 5 : 3. If the focal length of the concave lens is 15 cm, then the nature and focal length of the other lens would be [MP PET 1997]
A.	Convex, 9 cm
B.	Concave, 9 cm
C.	Convex, 25 cm
D.	Concave, 25 cm
Answer» B. Concave, 9 cm

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