It is desired to make an achromatic combination of two lenses, `(L_(1)& L_(2)) `made of materials having dispersive power `omega_(1) and omega_(2)(ltomega_(1))`. If the combination of lenses is converging then:

Derive the relation 1/f=1/f_1+1/f_2 for a combination of two thin lenses.

Ten identical wires each having a resistance of 1Omega are connected in parallel. The combination will have a resistance of

Two thin converging lenses of focal lenths 15 cm and 30 cm are held in contact with each other.Calculate power and focal length of the combination.

Two lenses have powers + 1 D and - 2 D respectively ,The power of combination si:

Two thin lenses of focal length f_1 and f_2 are in contact and coaxial.The power of the combination is

Find the angle fo a prism of dispersive power 0.021 and refractive index 1.53 to form an achromatic combination with prism of angle 4.2^@ and dispersive power 0.045 having refractive index 1.65.Find the resultant deviation.

An astronomical telescope uses two lenses of power 10 D and 1 D.What is its magnifying power in normal adustment?

If omega^(3)=1 and omega ne1 , then (1+omega)(1+omega^(2))(1+omega^(4))(1+omega^(5)) is equal to

The dispersive powers of the materials of the two lenses are in the ratio 4:3 .If the combination of these two lenses is of focal length 60 cm,then the focal lengths of the component lenses are:

Compare this power used in the 2omega resistor in each of the following circuits:- a 6V battery in series with 1 omega and 2 omega resistors, and