If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the iamage will be

If a lens is cut into two pieces perpendicular to the principle axis and only one part is used the new focal length.

An equiconvex lens of focal length20 cm is cut into two equal halves perpendicular to the principal axis and kept at a separation of 10 cm co-axially. What ils the focal length of the each part is?

Define the principal axis of a lens.

Focal length of an equiconvex lens is 20 cm. If we cut it once perpendicular to principal axis in and then along principal axis. Then, focal length of each part will be:

A thin biconvex lens of focal length 6.25 cm is made of material of refractive index 1.5. It is cut into two identical pieces perpendicular to its principal axis. One of the pieces is placed in water of refractive index 4/3 . The focal power of the piece immersed in water in diopter is