Refraction at a spherical surface

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Homework Help Overview

The discussion revolves around the concept of refraction at a spherical surface, specifically focusing on the use of refractive indices in different scenarios. Participants are exploring the transitions of light as it moves from one medium to another, particularly from air to glass and back to air.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the assignment of refractive indices in different parts of the problem, particularly why n1 changes from 1.00 to 1.50 and then back to 1.00. There is a focus on understanding the starting point of the light and the implications of its path through the spherical surface.

Discussion Status

Some participants have offered insights into the reasoning behind the refractive index assignments, suggesting that the light begins in the sphere rather than in a vacuum. There is an ongoing exploration of the implications of this understanding, with some participants expressing clarity after discussing the problem.

Contextual Notes

There appears to be some confusion regarding the initial conditions of the light's path and the definitions of the refractive indices used in the problem. Participants are actively clarifying these assumptions.

stpmmaths
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Homework Statement



attachment.php?attachmentid=20107&stc=1&d=1250245914.jpg


Homework Equations





The Attempt at a Solution



I was kind of confuse with the use of refractive index.

For the first part of question, n1 = 1.00 and n2 = 1.50. From what I know, the object is at vacuum so the n1 = 1.00.

But why for the second part of the question, n1 = 1.50 and n2 = 1.00 ? After the first refracting surface, the image should be at the vacuum too. But why we use n1 = 1.50?
 

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Welcome to PF!

Hi stpmmaths! Welcome to PF! :smile:
stpmmaths said:
I was kind of confuse with the use of refractive index.

For the first part of question, n1 = 1.00 and n2 = 1.50. From what I know, the object is at vacuum so the n1 = 1.00.

But why for the second part of the question, n1 = 1.50 and n2 = 1.00 ? After the first refracting surface, the image should be at the vacuum too. But why we use n1 = 1.50?

(I can't see your attachment yet, but …)

I assume that the light starts by going into the sphere from the air (or vacuum), so it's going from n = 1 to n = 1.5;

then it travels through the sphere (n = 1.5) until it hits the opposite surface and comes out again, so it's going from n = 1.5 to n = 1. :wink:
 
tiny-tim said:
Hi stpmmaths! Welcome to PF! :smile:(I can't see your attachment yet, but …)

I assume that the light starts by going into the sphere from the air (or vacuum), so it's going from n = 1 to n = 1.5;

then it travels through the sphere (n = 1.5) until it hits the opposite surface and comes out again, so it's going from n = 1.5 to n = 1. :wink:

Ok..I understand a bit.

Now I came across with another question similar to this question(quite similar)

Quenstion:
attachment.php?attachmentid=20113&stc=1&d=1250304700.jpg

Answer:
attachment.php?attachmentid=20114&stc=1&d=1250304700.jpg


Why the n1 is 1.50 if we say the light starts from vacuum?:confused:
 

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stpmmaths said:
Why the n1 is 1.50 if we say the light starts from vacuum?:confused:

Because the light starts from the coin, inside the sphere, not from vacuum. :wink:
 
stpmmaths said:
Why the n1 is 1.50 if we say the light starts from vacuum?:confused:

Look carefully at the arrows in the figure. Where do they start from?

EDIT: to clarify, look at the interface where the two rays meet. The ray arrows indicate they go from the glass into the air.

p.s. Hello tiny-tim!
 
Oo, I got it.
Thanks everyone.
 

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