AAMC FL 1 C/P Question 45
AAMC FL 1 C/P Question 45
Can someone please help me on this lens equation. Obviously, my math is off somewhere. Thank you.

 Posts: 538
 Joined: Fri May 25, 2018 9:15 am
Re: AAMC FL 1 C/P Question 45
Thanks for the question!
Q45 is definitely a tricky one since they don't give you numbers and are asking for a ratio!
Copying the below from an old post (viewtopic.php?f=16&t=317&p=1355&hilit=f ... 86d0#p1355):
Q45 is definitely a tricky one since they don't give you numbers and are asking for a ratio!
Copying the below from an old post (viewtopic.php?f=16&t=317&p=1355&hilit=f ... 86d0#p1355):
I hope this helps! Feel free to ask any clarifying questions if something isn't clear!This question requires us to use the thin lens formula and magnification.
Starting with what's given to us, we can see that the object distance is 3 times the focal length, or in other words o=3f.
The thin lens formula is 1/f = 1/o + 1/i. From here we can plug in our numbers, move things around and find out what i is in terms of f.
1/f = 1/3f + 1/i
3/3f 1/3f = 1/i
2/3f = 1/i
i = 3/2f
Now let's go back to question stem, it asks for the ratio of the height of the image to the height of the object, this is essentially magnification. i is 3/2f, o is 1/3f, so our ratio is 1/2.