Simple thinking problem - mirror refraction

In summary, the camera lens should be focused at a distance that is twice the distance from the camera to the mirror, as the image in a plane mirror is the same distance behind the mirror as the object is in front of the mirror.
  • #1
airkapp
58
0
Suppose you want to take a photograph of yourself as you look at your image in a flat mirror 1.8 m away. For what distance should the camera lens be focused?

You must be ½ the total distance away: since the angle of incidence is equal to the angle of reflection, the distance needed to get a full view is ½ the total distance.

1.8 / 2 = .9 m


seems to easy. Is that right? :bugeye:
 
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  • #2
No. Instead, ask yourself: how far away from you is your image in the mirror? That's the distance you need to focus the camera. (The camera, like your eye, knows nothing about mirrors. If the object (in this case, your image) looks 10 feet away, then you need to focus for 10 feet.)

(Hint: The image in a plane mirror is the same distance behind the mirror as the object is in front of the mirror.)
 
  • #3
Doc Al said:
No. Instead, ask yourself: how far away from you is your image in the mirror? That's the distance you need to focus the camera. (The camera, like your eye, knows nothing about mirrors. If the object (in this case, your image) looks 10 feet away, then you need to focus for 10 feet.)

(Hint: The image in a plane mirror is the same distance behind the mirror as the object is in front of the mirror.)


okay, I'm thinking it's just 1.8 m, but still to easy.


You're hint is kinda throwing me off. heh. but then it sounds like it should be 1.8 since I am only 1.8 m away and thus camera lens needs to be 1.8 m away since it acts in accordance w/me eye.

correct?
 
  • #4
Look at his hint more closely...He says The image in a plane mirror is the same distance behind the mirror as in front...so think about it.
 
  • #5
Satoy said:
Look at his hint more closely...He says The image in a plane mirror is the same distance behind the mirror as in front...so think about it.

okay then obviously there is no distance this is simply the mirror of the distance of the object.?
 
  • #6
No...Pictures are made after light is exposed to film...Take one piece of light as follow it in your mind the distance from the film to the mirror...reflected...and back to the film...what is the distance?
 
  • #7
Satoy said:
No...Pictures are made after light is exposed to film...Take one piece of light as follow it in your mind the distance from the film to the mirror...reflected...and back to the film...what is the distance?

twice the distance. ?
 
Last edited:

1. How does refraction work in a mirror?

Refraction in a mirror occurs when light passes through the interface between two different mediums, in this case, air and glass. The change in density between these two mediums causes the light to bend, resulting in the reflection we see in a mirror.

2. Why is my reflection in a mirror reversed?

The reversal of our reflection in a mirror is due to the way light bounces off the mirror's surface. When light hits a flat surface, it reflects back at the same angle it came in. This means that the left side of our face is reflected on the right side of the mirror and vice versa.

3. Can a mirror produce multiple reflections?

Yes, a mirror can produce multiple reflections. This is known as an infinite reflection or an infinite hallway effect. It occurs when the reflected light from one mirror bounces onto another mirror and then reflects back onto the first mirror, creating a never-ending series of reflections.

4. How does the angle of incidence affect the angle of reflection in a mirror?

The angle of incidence, which is the angle at which light hits the mirror, is equal to the angle of reflection, which is the angle at which the light bounces off the mirror. This is known as the law of reflection and is true for all smooth, flat surfaces.

5. Can a mirror change the size of an object's reflection?

Yes, a mirror can change the size of an object's reflection. This is due to the fact that the size of the reflection is determined by the distance between the object and the mirror. If the object is closer to the mirror, the reflection will appear larger, and if it is further away, the reflection will appear smaller.

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