Focal lengths of two lenses are f and f and dispersive powers of their materials are omega and omega^(')'. To form achromatic combination from these, which relation is correct?

Focal lengths of two lenses are f and f and dispersive powers of their

1.	Focal lengths of two lenses are f and f and dispersive powers of their materials are omega and omega^(')'. To form achromatic combination from these, which relation is correct?
Answer» `omega=omega_(0), 2omega_(0), F^(')=2f` `omega=omega_(0), 2omega_(0), f^(')=-2f` `omega=omega_(0), 2omega_(0), f^(')=f/2` `omega=omega_(0), 2omega_(0), f^(')=-f/2` Answer :B

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Focal lengths of two lenses are f and f and dispersive powers of their materials are omega and omega^(')'. To form achromatic combination from these, which relation is correct?

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