Question

2. A convex lens with focal length f centimeters will project the image of an object on a point behind the lens. If an object is placed a distance of p centimeters from the lens, then the distance q centimeters of the image from the lens is related to p and f by the lens equation: 1/p + 1/q = 1/f

Answer 1

The diagram looks like this:
object------------*---f---lens---*---image

From object to lens is p and from lens to image is q.

A. If the focal length of the convex lens is supposed to be 5 cm, and if the image is formed 7 cm from the lens, find the distance, p, from the lens to the object. (It’s not necessary to simplify your answer.)

I have concluded that the answer for this is 2/35 or 17.5 cm. (1/5 – 1/7 = 1/p
= 2/35) Please correct me if I am wrong.

Answer 2

My real question is:
B. Find an expression that gives q as a function of p, assuming that the focal length is a constant of 5 centimeters.

I am not sure how to go about this. Q(p) will be substituted for f(x) and that is all know.

Please help me any way you can!
I posted the answer to my first question so that it would help you guys understand better.

Answer 3

The first part looks good to me. For the second part, I started out with 1/p +1/q = 1/5 and I solved for q.

Answer 4

Do you need the steps? It is quite a few.

Answer 5

My final answer is q= 5p/(-5+p)

Answer 6

Please give the steps if you are willing. :)

Answer 7

Please enjoy the attached SyncSpace drawing
infinitekind.com/syncspace

Answer 8

Darn. It didn't work. Hold on. I am learning how to work this site.

Answer 9

http://www.tutormatchingservice.com/K17CB
You should be able to see the work on this site. Let me know if you have a problem.

Answer 10

Thank you so much for your help! :)

Answer 11

You're welcome.