How Do Similar Triangles Derive the Thin Lens Equation?

Click For Summary
SUMMARY

The discussion focuses on the derivation of the thin lens equation using similar triangles, specifically triangles ABD and EDF. The key takeaway is that the relationship between the triangles leads to the formula di/f - 1. The derivation involves concepts such as refraction at spherical surfaces and utilizes Fermat's principle along with the small angle approximation. For a comprehensive understanding, the reference "Optics" by Hecht is recommended as it provides detailed insights into the derivation process.

PREREQUISITES
  • Understanding of similar triangles and their properties
  • Familiarity with the thin lens equation and its components
  • Knowledge of refraction principles, particularly at spherical surfaces
  • Basic grasp of Fermat's principle and small angle approximation
NEXT STEPS
  • Study the derivation of the thin lens equation in detail
  • Learn about refraction at spherical surfaces
  • Explore Fermat's principle and its applications in optics
  • Review the small angle approximation and its relevance in lens equations
USEFUL FOR

This discussion is beneficial for physics students, optical engineers, and educators seeking to deepen their understanding of lens optics and the mathematical principles behind the thin lens equation.

Larrytsai
Messages
222
Reaction score
0
kk so i found out the steps involved deriving the thin lens equation, but what i don't get is when you have 2 similar triangles say triangle abd,edf are congruent how does the 2 triangles make it so its di/f-1. so what I am basically asking is can someone thourougly explain to me what's going on in the steps to deriving the thin lens equation thnx.
 
Physics news on Phys.org
Remember: the thin lens equations are only approximation to the real world. one way to get these formulas is to study refraction at spherical surfaces using Fermat's principle and small angle approximation, amongst other things. It is not a straight forward derviation. See for example: "Optics" by Hecht
 

Similar threads

Replies
1
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
Replies
8
Views
6K
  • · Replies 10 ·
Replies
10
Views
4K
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
6K