The dispersive powers of crown and flint glasses are 0.02 and 0.04 respectively. In an achromatic combination of lenses the focal length of flint glass lens is 40 cm. The focal length of crown glass lens will be

Two thin lenses of focal length f_1 and f_2 are placed in contant .The focal length of the composite lens will be

The dispersive pwoers of crown and flint glasses are 0.03 and 0.05 respectively.If difference in the refrative indices for blue and red colour is 0.015 for crown glass and 0.022 for flint glass,calculate the angles of the two prisms for a deviation of 2^@ without dispersion.

Power of a lens is -5d, its focal length is:

If the focal length of a converging lens is 50 cm. What is the power of the Lens ?

Find the focal length of a lens of power- 2.0 D.What type of lens this?

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:

The focal length of a plane glass plate is infinite and its power is zero.

How does the focal length of a glass lens change when blue light is replaced by red light. Give reasons.

Write expression for the focal length and power of a lens combination.