Lenses- magnification adn focal length

  • #1

Homework Statement


Hey,,
I was wondering if anyone could help me with some physics work i am doing as i am completly stuck.
Is there supposed to be any relationship with the magnification and focal length of lenses and if so what is it?
I did an experiment and measure the magnification of lenses different distances from the lenses and also calculated the focal length at these points. Now i am stuck on how to write all this up and what graphs to draw.
Any help would be much appreciated :s
xxx


Homework Equations



I used 1/v-1/u=1/f for focal length
and size of image/ size of object for magnification

The Attempt at a Solution

 

Answers and Replies

  • #2
tiny-tim
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Welcome to PF!

Hi PhysicsChick8! Welcome to PF! :smile:

See the PF Library entry on lens :wink:
 
  • #3
thanks i read that but i'm kinda very bad at physics and need it explained in very simple terms if possible without too many confusing equations xx
 
  • #4
tiny-tim
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As the Library says …

The image is magnified (with respect to the size of the object) by the factor m = -di/do

and …

do is positive for a real object and negative for a virtual object (See Images section).
di is positive for a real image and negative for a virtual image (See Images section).

and …

For the common situation where the object and image are real (do and di both positive), the magnification is negative indicating an inverted image with respect to the object.
 
  • #5
so if i were plotting stuff on a graph what would i plot? x
 
  • #6
tiny-tim
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Well, what are you trying to show? :smile:
 
  • #7
thats the problem i don't know,,, we had to choose an experiment and i choose the magnification and power of lenses as it seemed easy. Now i have to write it up and draw graphs but im not sure what of as i don't really know what is linked. I really am useless at this if you haven't guessed already x
 
  • #8
tiny-tim
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I suppose the obvious graphs would be di against do, and m (= -di/do) against do.

Try drawing them, and see what you get. :smile:
 
  • #9
thank you :D x
 

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