Can two lenses of the same material produce achromatism when placed in contact? Explain.

Show that the power of the achromatic combination of two convex lenses of the same material is equal to the mean power of the lenses.

It is required to from a converging achromatic system of length 30m consistng of two lenses made of the the same matrial. If one lenses be convex and of focal length 0.20m, find (a) the foocal length of the other and also (b) the distance between the lenses.

Two wires A and B of the same material and having same length, have their cross-sectional areas in the ratio 1 : 6 . what should be the ratio of heat produced in these wires when same voltage is applied across each ?

Two wires A and B of the same material and having same length, have their cross-sectional areas in the ratio 1:4 . what should be the ratio of heat produced in these wires when same voltage is applied across each ?

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.

Deduce the equivalent focal length of two convex lenses of focal lengths F_(1) and F_(2) when placed in contact.

Assertion : Two convex lenses joined together cannot produce an achromatic combination Reason : The condition for achromatism is (epsilon_(1))/( f_(1)) + (epsilon_(2))/( f_(2)) = 0 where bols have their usual meaning