Concave Lens Equation Derivation: Understanding the Role of Refractive Index

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Homework Help Overview

The discussion revolves around the derivation of the concave lens equation, particularly focusing on the role of the refractive index in the context of a fish in a fish bowl scenario.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to derive the equation but finds discrepancies between their result and the provided solution. They question the cancellation of the refractive index in the equation.

Discussion Status

Participants are actively discussing the derivation process and the application of the lens formula. Some guidance has been offered regarding the setup of the equation, and there is acknowledgment of the refractive indices involved.

Contextual Notes

There is a mention of specific values for the refractive indices and the setup of the problem, including the positioning of the fish within the bowl. The original poster's confusion about the cancellation of terms indicates a need for clarification on the assumptions made in the derivation.

Daniiel
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Hey
this is a pretty straight forward equation derivation, but when i do it and compare it to the solutions, mine is different to theirs.
The equation is
[PLAIN]http://img213.imageshack.us/img213/9790/ddaaad.jpg where n1=1
for a concave lens (fish in a fish bowl) so r is negative

solving for i

they get, r/(n2+1)

and i get n2r/(n2+1)

there answer seems right for the question, but I am just not sure how they canceled the n2
 
Last edited by a moderator:
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Post the actual problem in the book.
 
[PLAIN]http://img228.imageshack.us/img228/593/dsdsdsaas.jpg

p = r/2 n2 = water
 
Last edited by a moderator:
The fish is inside the bowl. So the formula becomes

n1/p + n2/i = (n1 - n2)/r

Here n1 = 1.33 and n2 = 1.

Now simplify and find i.
 
oh right
thanks a lot
 

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