Optics,how many images will the object form?

[mero coactail]

optics,how many images will the object form?

Homework Statement

the lens shown in figure 19.16(http://img705.imageshack.us/img705/5066/figure1916.png made of two different materials . a point object is placed on the axis...how many images will the object form?

Homework Equations

1/f = (n-1) [1/R1 - 1/R2], where f is the focal length, n is the refractive index, R1,R2 - radii of the curvature of refracting surfaces.

The Attempt at a Solution

i didnt reach the answer but i think it has something with refractive index , and focal lenth...please help..

 

[mero coactail]

ya forgot the choices

a)one

b)two

c)three

c)no image

 

[AJ Bentley]

If you just had the middle bit of the lens, would it form an image, more than one image, or none?