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

Obtain the formula for combined focal length of two thin lenses in contact, taking one divergent and the other convergent.

How do magnification and focal length change for a combination of thin lenses ?

Derive the relation : (1)/(F) =(1)/(f_(1)) +(1)/(f_(2)) ,where f_(1) and f_(2) are focal length of two thin lenses and F is the focal length of the combination in contact.

We combined a convex lens of focal length f_(1) and concave lens of focal lengths f_(2) and their combined focal length was F . The combination of these lenses will behave like a concave lens, if

A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm. The focal length of this combination of lenses will be:

Two thin lenses, aone convex of focal length 10 cm and other concave lens are kept in contact to form a composite lens of focal length 13 cm . If the combination acts as a converging lense the focal length of second lens is

Arrange the following combinations in the increasing order of focal length Two piano convex lenses of focal lengths 15 cm and 30 cm in contact Two convex lens of focal lengths 40 cm and 50 cm in contact Two convex lenses of focal length 20 cm separated by 5 cm