Optics - For what distance must we focus our eyes to see this image

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Homework Help Overview

The discussion revolves around an optics problem involving a plane mirror, where an object is placed in front of the mirror and an observer stands behind it. The participants explore how far the observer must focus their eyes to see the image of the object.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between the object and its image in a plane mirror, questioning the image's location and distance from the observer. Some express uncertainty about whether the image is in front of or behind the mirror.

Discussion Status

There is an ongoing exploration of the problem, with participants offering hints and questioning each other's reasoning. Some guidance has been provided regarding the nature of images formed by plane mirrors, but no consensus has been reached on the final interpretation of the distances involved.

Contextual Notes

Participants are navigating the concepts of virtual images and distances in relation to the observer and the object, with some expressing confusion about the setup and the implications of the mirror's properties.

Kathi201
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An object is placed 1m in front of a plane mirror. An observer stands 3m behind the object. For what distance must the observer focus his eyes in order to see the image of the object?
 
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5 metres? Was that all there is to the question?
 


Yeah that is all the question was. How did you figure that out?
 
Kathi201 said:
An object is placed 1m in front of a plane mirror. An observer stands 3m behind the object. For what distance must the observer focus his eyes in order to see the image of the object?

Hi Kathi!

Hint: for a plane mirror, where is the image in relation to the object? :smile:

(Hi Mentallic: please don't give out answers! :wink:)
 


Do you mean that it is in an angle? I am not quite sure of the answer you are looking for
 
Kathi201 said:
Do you mean that it is in an angle? I am not quite sure of the answer you are looking for

Mirrors are like lenses … every object has an image.

For a plane mirror, where is the image of an object? :smile:
 


The image is located in front of the mirror. Isn't the image distance equal to the object distance. Thus it would be 3m
 


Ok so now that I am thinking about, is the image behind the mirror or in front. I am starting to think it is behind?
 
Kathi201 said:
Ok so now that I am thinking about, is the image behind the mirror or in front. I am starting to think it is behind?

Yup, the image is definitely behind the mirror! :biggrin:

(It's a virtual image: the rays of light "from" it don't actually get anywhere near it, do they? :smile:)

Sooo … how far away from the observer is the image of that object she's standing behind?​
 
  • #10


The object is 1m away and the person is 3m away so it would be 3m +1m + the 1m behind the mirror so it would be 5m.
 
  • #11
That's it!

Any questions? :smile:​
 

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