Anyone have a quick and easy way to remember the "positives" and "negatives" for the object distance and image distance. This applies to both mirrors and lenses.
I actually learned this in my Physics 2 class at the very end of the semester, so it was nice and fresh for the OAT. This isn't a special easy way, but this is how we did it. Based on my memory, on a sheet of paper we drew a line down the middle. On the left side we had Converging. This includes concave mirrors and convex lenses; real images are produced (with one exception) in which case the image distance is positive. This means the image is where you would expect it to be in real life! For a lens, it goes through the lens so the image is on the other side of the object. For a mirror, it gets reflected so the image is on the same side as the object.
On the right side of the paper, we had Diverging. This includes convex mirror and concave lens. Virtual images are always produced! Meaning the image is on the same side as the object with a lens, or on the opposite side with a mirror! This means that image distance is always negative!
In ALL cases, object distance is positive, so you don't have to memorize this. Oh, and the whole point of the piece of paper is just that this is what I used to memorize it, and when I had to refer to it during practice.
If I'm wrong, someone please correct me
🙂
