Optics: finding the width of an image produced through a lens

1. Apr 30, 2012

randomperson

1. The problem statement, all variables and given/known data

This is more of a general conceptual question.

When finding the image produced through a convex or concave lens, I know that you can use the equation magnification = (height of image/height of object) to find the magnification of the image produced. But does this proportion extend to the width of the object and image as well?

For example, if I had an object that was 5 inches tall and 6 inches wide, and the magnification was -2, what would be the dimensions of the image produced?

2. Relevant equations

mag = hi/ho = -di/do

3. The attempt at a solution

I know that the height of the image would be is -10 inches. Would the width of the image simply be -12 inches?

Also if that is how you find it, would width be given as a positive value or negative value? The height would be negative by convention because the image is flipped, but is width is negative as well? (I’m thinking yes, because when an image is inverted, you see an upside down and backwards image, so the left side of the object shows up on the right side of the image, etc.)