A camera lens (f=0.20m) is made of two components, one of crown glass (dispersive power 0.02) and the other of flint glass (dispersive power 0.04) Find the focal length of the component lenses.

A converging system of convex lenses free from chromatic aberration and of focal length 2.5 cm is to be constructed by using a convex lens of focal length 2 cm and dispersive power 0.04 and another convex lens of dispersive power 0.03. What should be the focal length of the second lens and at what distance from the first lens should it be placed ?

The power of a lens of focal length 0.5 m is :

The power of a lens of focal length 0.5 m is :

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 achromatic coverging combination of focal length 0.3 m when placed in contact.

A achromatic combination is made with a lens of focal length f and dispersive power omega with a lens having dispersive power of 2omega . The focal length of second will be

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 contact. Find the focal length of each lens.

An achromatic lens-doublet is formed by placing in contact a convex lens of focal length 20 cm and a concave lens of focal length 30 cm. The dispersive power of the material of the convex lens is 0.8. Determine the dispersive power of the material of the concave lens. Calculate the focal length of the lens-doublet.