A converging lens of focal length f = 8.96 cm forms a sharp image for two positions of the lens

  • Thread starter aeroboi
  • Start date
  • #1
aeroboi
2
0
Homework Statement:
The distance between an object and its image is fixed at 40.0 cm. A converging lens of focal length f = 8.96 cm forms a sharp image for two positions of the lens. What is the distance between these two positions?
Relevant Equations:
f=(s*s')/(s+s')
s'=(sf)/(s-f)
I am aware that the object would be to the left of the lens and the image would be to the right, but I don't understand what it is mean by " A converging lens of focal length f = 8.96 cm forms a sharp image for two positions of the lens." I don't understand where the two positions would be and why two positions are produced.

I'd appreciate any help visualizing this and a push for an approach. Thanks!
 

Answers and Replies

  • #2
kuruman
Science Advisor
Homework Helper
Insights Author
Gold Member
12,601
5,751
It means that if you fix the distance between the object and the image (##s+s'##) there are two possible choices for the values of ##s## and ##s'##.
 
  • #3
aeroboi
2
0
It means that if you fix the distance between the object and the image (##s+s'##) there are two possible choices for the values of ##s## and ##s'##.
Ok... but isn't that distance just 40cm (as stated in the problem statement)?
 
  • #4
kuruman
Science Advisor
Homework Helper
Insights Author
Gold Member
12,601
5,751
Ok... but isn't that distance just 40cm (as stated in the problem statement)?
Yes, that's what it is. By using the thin lens equation you can find the two values of ##s##, ##s_1## and ##s_2## that would provide an image to object distance ##d=40~\mathrm{cm}##. Assuming that you have found them, how can you use them to find what the problem is asking?
 

Suggested for: A converging lens of focal length f = 8.96 cm forms a sharp image for two positions of the lens

  • Last Post
Replies
8
Views
449
Replies
1
Views
385
Replies
7
Views
344
  • Last Post
Replies
1
Views
175
Replies
3
Views
325
Replies
5
Views
530
Replies
1
Views
2K
Replies
26
Views
1K
Replies
3
Views
395
Replies
3
Views
1K
Top