Can anyone help me with optics?

[Ari1584]

okay so i just went through the TBR section of optics and the kaplan one...and i am SO confused on all of it. And the ray tracing part i NEVER understood. So i was wondering if anyone can help me remember the "rules" for when something is inverted, virtual or real, etc etc. I remember certain things like inverted images are always real and virtual are upright, but i get VERY confused on questions like : "what happens when you place an object within the focal point of a convex lens, and then move it to outside the focal point". I can never seem to grasp the tecnique to figuring this out and even when i just try to memorize the rules i always get the wrong answer. I need to understand WHY the answers are what they are. Oh also, are you guys learning the ray tracing method as well? thanks for any help!!

---

Members don't see this ad.

 

[Phlame217]

I was taught the ray tracing method in my class, but for the mcat its very time consuming and should be used only as a last resort.

EK has a good and quick review for lenses and mirrors so you might look into their review.

 

[aevea]

I like using RIP VUN Winkle for images. RIP= Real, Inverted, Positive; VUN=Virtual, Upright, Negative; and Winkle=winkle .

In addition, you need to know that MCAT object distances are almost always going to be positive. Convex mirrors and diverging lenses (skinnier in the middle) scatter light, so they only make VUN images and have -f.

Concave mirrors and converging lenses (fatter in the middle) focus light, so they have +f and can make RIP images if the objects aren't too close. But if their objects are inside the focal length, they don't have the power to pull the rays together, so their images are also VUN.