Does a Silvered Plano-Convex Lens Act Like a Concave Mirror?

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Homework Help Overview

The discussion revolves around the optical behavior of a silvered plano-convex lens and whether it functions like a concave or convex mirror. Participants are examining the implications of the lens's geometry and the effects of silvering the plane surface.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to analyze the behavior of light rays as they pass through and reflect from the lens, leading to a conclusion that it behaves like a convex mirror. However, they note a discrepancy with their textbook and online sources suggesting it acts like a concave mirror. Other participants question the assumptions made about the angles of refraction and the nature of the diagrams used to illustrate the problem.

Discussion Status

Participants are actively engaging with the problem, with some providing external resources for further exploration. There is a mix of interpretations regarding the lens's behavior, and while some guidance has been offered, there is no explicit consensus on the correct classification of the lens's function.

Contextual Notes

The original poster mentions an urgency due to upcoming exams, indicating a time constraint that may affect the depth of discussion. There are also references to diagrams that may not be universally understood, suggesting a need for clearer visual aids in the explanation of the optical principles involved.

sarthak sharma
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If the plane surface of a plano-convex lens in silvered then which of the following statements is true?

1. it acts like a convex mirror
2. it acts like a concave mirror
3. it acts like a concave lens
4. no changemy attempt---

the incident ray on the convex surface of the plano-convex will first converge (refract) then reflect from silvered plane surface towards the first surface and then from there it will diverge (refract again) towards the incident side only.

so i came to a conclusion that the combination is diverging on the same side as object and thus it acts like a Convex Mirror

but my book give the answer as a concave mirror and the same answer i get after browsing the net but could not find a proper explanation for itcan someone please help me out asap as my exams are pretty much close now...
 
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sarthak sharma said:
from there it will diverge (refract again) towards the incident side only.
.
Are you sure? In your diagram, make sure you draw quite modest refractions so that you don't confuse yourself.
 
haruspex said:
Are you sure? In your diagram, make sure you draw quite modest refractions so that you don't confuse yourself.

@haruspex i think i kind of get what you want to say that angle of refraction are not very much large...
so the diagram given above by @ehild would be an ideal diagram
and going by it it is pretty much clear that the incident rays converge on the same side on a point on the pricipal axis and hence it acts like a Concave Mirror
confirm it if you agree...
 
sarthak sharma said:
@haruspex i think i kind of get what you want to say that angle of refraction are not very much large...
so the diagram given above by @ehild would be an ideal diagram
and going by it it is pretty much clear that the incident rays converge on the same side on a point on the pricipal axis and hence it acts like a Concave Mirror
confirm it if you agree...
Yes.
 

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