- #1

mortymoose

## Homework Statement

Two convergent lens are identical in focal length (

*f*=10cm) and the oobject height (

*h0)*is 3.5 cm. The distance between the two lenses is 30cm and the distance from the object to the first lens is 30cm.

-Draw a diagram on the figure and show the image position (

*di)*and size (

*hi)*formed by the two lenses.

## Homework Equations

1/f = 1/s' +1/s

h'/h = - s'/s

## The Attempt at a Solution

The first place I think I am getting confused is whether or not two images are formed. When I did my work that is what i assumed.

My first step was to solve for the first image location:

1/10 = 1/30 +1/s'

s' =15cm

so, first imag eis 15cm in front of first lens

then the height of the first image:

h'/3.5cm = -15/30

h'= -1.75cm

Second image location:

1/10=1/25 +1/s'

s'= 16.6cm

the second image is 16.6cm in front of the second lens

height of second image was:

h'/-1.75cm = -16.6cm/15cm

h'= 1.9cm

So this image would be real, inverted, and reduced in size

But then I am supposed to use 1/

*d0 + 1/di =1/f*

and that's where i realized i must be doing something wrong, because I assumed that two images would be formed but they are only asking for the one image