Understanding Virtual Images in Lenses and Mirrors

[whitehorsey]

1. A stamp collector uses a converging lens with focal length 32 cm to view a stamp 17 cm in front of the lens.

Where is the image located?
a. in front of the lens (real image)
b. behind the lens (virtual image)


2. 1/f = 1/do + 1/di


3. 1/32 = 1/17 + 1/di
di = -32.267 cm

Because it's negative it is a virtual image.

For this problem, I imagined

front behind
---f--do---lens-----------

A virtual image is in the same side as the object. So something like this:
http://www.pa.msu.edu/courses/2000fall/PHY232/lectures/lenses/virtual_image.gif


So then why does the answer say if its virtual it is behind the lens? Also, what is considered front/behind for lens/mirrors?

 

[Basic_Physics]

I think it is referring to the viewer. Behind the lens for the viewer is in front for the lens.

 

[whitehorsey]

Thank You!