Lenses#!#Combination of Lenses#!#Displacement Method

Power and Combination OF Lenses and Mirrors

Examples on Lenses

Shashank went to the optician to get his eyes checked. He observed that the doctor combined two lenses and put these in front of his eyes so that he could see clearly. The powers of the two lenses used in the combination were -3 D and 4 D. Which of these will be the focal length of the combination of lenses Shashank has to wear?

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:

A convex lens of power 5 D and a concave lens of power 7.5 D are placed in contact with each other. What is the: a) power of this combination of lenses? b) focal length of this combination of lenses?

Obtain an expression for focal length of a combination of thin lenses in contact.

Pure and combination OF lenses and mirrors