# Converging lens test question

## Homework Statement

There is an object 20 cm from a converging lens with a 10 cm focal length.

## Homework Equations

Is the image upright or inverted?
Calculate the image distance.
Calculate the image height.

## The Attempt at a Solution

I just had this on a college test in a testing center, I could find the first two with the thin lens equation and diagrams, not sure how I was supposed to get the last. I feel some info was missing, like object height. Any way my feeling was wrong?

Your feeling wasn't wrong since there is not enough information to find the image height.For this question the image height equals the object height (magnification equals one) but the object height was not given.

SammyS
Staff Emeritus
Homework Helper
Gold Member
Hi kikko.

I agree, there's not enough information for an absolute answer, but you could give a relative answer, like, 2 × the object height, or 1/3 the object height or the same as the object height.

Your feeling wasn't wrong since there is not enough information to find the image height.For this question the image height equals the object height (magnification equals one) but the object height was not given.

its possible that they meant magnification, because i had a similar problem on midterms when i was in optics