Apparent distance of object in planar mirror

  • Thread starter leehom
  • Start date
  • Tags
    Mirror
In summary, Tanya is sitting in an optometrist's chair facing a mirror that is 2.25 m from her eyes. The eye chart she is looking at is hanging on a wall behind her head, 1.75 m behind her eyes. The chart appears to be 6.25 m away from the mirror due to the use of a plane mirror. The angle of reflection from the original reflected light will decrease by 8 degrees when the plane mirror is tilted, following the law of reflection.
  • #1
leehom
24
0
Tanya is sitting in an optometrist’s chair, facing a mirror that is 2.25 m from her eyes. It the eye chart she is looking at is hanging a wall behind her head, 1.75 m behind her eyes. How far from her eyes does the chart appear to be?

Would the answer be 4 m? (2.25 m +1.75 m)... I'm assuming it's a plane mirror
 
Physics news on Phys.org
  • #2
Yes, it's this simple.

Do you need to provide any proof of your answer?
 
  • #3
Yeah... can i explain in words, that since it's a plane mirror, etc.
 
  • #4
BTW, is it possible for you to help me with a few other physics (optics) questions? I'm really really confused..
 
  • #5
Would it not be 6.25m? :confused:
 
  • #6
leehom said:
BTW, is it possible for you to help me with a few other physics (optics) questions? I'm really really confused..

Feel free to post any physics homework related questions in this forum.
 
  • #7
Kurdt said:
Would it not be 6.25m? :confused:

Whoops, yes it s. I didn't read the question closely.

Leehom: How far is the chart from the mirror?
 
  • #8
Chi Meson said:
Whoops, yes it s. I didn't read the question closely.

Leehom: How far is the chart from the mirror?

I'm sorry I don't understand where the 6.25 m came from... can you pls. explain?
 
  • #9
leehom said:
I'm sorry I don't understand where the 6.25 m came from... can you pls. explain?

Read the question and tell me: how far is the chart from the mirror?
 
  • #10
And why would charts used for this purpose have to be specially made?
 
  • #11
Chi Meson said:
Read the question and tell me: how far is the chart from the mirror?


I think I get it now... 2.25 m + 2.25 m + 1.75 m = 6.25 m...
 
  • #12
If you don't answer my question, I'm leaving.

Edit:

Phew! Just in time!
 
  • #13
Why do you think charts would have to be specially made?
 
  • #14
leehom said:
And why would charts used for this purpose have to be specially made?

Is this one of the questions? All optometrist's charts are "specially made."
 
  • #15
well... i wrote that the letters would have to "reversed" so that they would appear upright in the mirror according to prop. of images formed by a plane mirror...

and another quick verification on this question:
Light is shining on to a plane mirror at an angle of incidence of 27 deg. If the plain mirror is tilted such that the angle of incidence is reduce by 8 deg, what will be the total change in the angel of reflection from the original reflected light?

Would the change be 8 deg due to law of reflection? since the angle of reflection is calculated from the normal
 
  • #16
what will be the total change in the angel of reflection from the original reflected light?

Would the change be 8 deg due to law of reflection? since the angle of reflection is calculated from the normal

If you tilt the mirror, you tilt the normal. That means both the incident angle and the reflected angle increase by 8 degrees.
 
  • #17
But the question specifically states that the incident angle is reduced by 8 deg
 

1. What is the apparent distance of an object in a planar mirror?

The apparent distance of an object in a planar mirror refers to the perceived distance of the object when viewed in the mirror. It is the distance between the viewer's eye and the image of the object reflected in the mirror.

2. How is the apparent distance of an object in a planar mirror different from the actual distance?

The apparent distance of an object in a planar mirror is different from the actual distance because it is an optical illusion created by the reflection in the mirror. The image of the object appears to be the same distance behind the mirror as the actual object is in front of the mirror, but in reality, the image is the same distance from the mirror as the object is.

3. Does the size of the mirror affect the apparent distance of an object?

No, the size of the mirror does not affect the apparent distance of an object. The apparent distance is solely dependent on the distance between the viewer's eye and the mirror, as well as the distance between the object and the mirror.

4. Can the apparent distance of an object in a planar mirror be manipulated?

Yes, the apparent distance of an object in a planar mirror can be manipulated by changing the angle at which the object is placed in front of the mirror. By adjusting the angle, the perceived distance of the object in the mirror can be altered.

5. How does the apparent distance of an object in a planar mirror relate to the concept of depth perception?

The apparent distance of an object in a planar mirror is related to the concept of depth perception because it is an example of how our brain interprets visual cues to determine distance and depth. The reflected image in the mirror appears to be at a certain distance, but our brain uses other visual cues to understand that the image is actually at the same distance as the object in front of the mirror.

Similar threads

Calculating the Distance of an Eye Chart: Tanya's Story
    • Introductory Physics Homework Help
Replies
2
Views
1K
[LENS] Given focal length and height, find object distance
    • Introductory Physics Homework Help
Replies
1
Views
2K
Can You Focus on Two Distances at Once?
    • Introductory Physics Homework Help
Replies
1
Views
1K
Magnification at a Different Distance from Mirror?
    • Introductory Physics Homework Help
Replies
1
Views
1K
Light and Optics: Shoplifter's Distance and Height
    • Introductory Physics Homework Help
Replies
1
Views
1K
Object Height In a Plane Mirror
    • Introductory Physics Homework Help
Replies
2
Views
6K
Depth effect in mirror reflections
    • Optics
Replies
24
Views
14K
Angular magnification of flat and concave mirrors
    • Introductory Physics Homework Help
Replies
1
Views
4K
How Far Are the Closest Four Images of the Candle in the Mirrored Room?
    • Introductory Physics Homework Help
Replies
1
Views
4K
(Optics) Why is lecturer in risk of getting speeding ticket?
    • Introductory Physics Homework Help
Replies
10
Views
2K

Hot Threads

Recent Insights

Back
Top