Why Was My Answer of 63 cm for the Focal Length of a Converging Lens Incorrect?

  • Thread starter Thread starter syllll_213
  • Start date Start date
Click For Summary
SUMMARY

The focal length of a converging lens cannot be 63 cm given the parameters of the problem. The object distance is 14 cm, and the virtual image is located 18 cm from the object, resulting in an image distance of -4 cm (since virtual images are represented as negative distances). Using the lens formula (1/f = 1/v - 1/u), the correct focal length is calculated to be -2.8 cm, confirming that the initial answer of 63 cm is incorrect.

PREREQUISITES
  • Understanding of the lens formula (1/f = 1/v - 1/u)
  • Knowledge of object distance and image distance in optics
  • Familiarity with the concept of virtual images in converging lenses
  • Basic principles of geometric optics
NEXT STEPS
  • Study the derivation and application of the lens formula in optics
  • Learn about the characteristics of virtual and real images produced by lenses
  • Explore the differences between converging and diverging lenses
  • Investigate practical applications of lenses in optical devices
USEFUL FOR

Students studying optics, physics educators, and anyone seeking to understand the principles of lens behavior and image formation.

syllll_213
Messages
17
Reaction score
1
Homework Statement
An object is in a distance of 14 cm from a converging lens. The lens produces a virtual image at a distance 18 cm from the object.

What is the focal length of the lens (in cm).
Relevant Equations
1/f = 1/di + 1/do
1744709958617.png

I attempted and keyed in the answer as 63 but I was graded wrong. What am I missing?
 
Physics news on Phys.org
syllll_213 said:
Homework Statement: An object is in a distance of 14 cm from a converging lens. The lens produces a virtual image at a distance 18 cm from the object.
 
  • Like
Likes   Reactions: Tomy World

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K