Object Distance for Mirrors versus Lenses

In summary, the conversation discusses the confusion around the sign convention for object distance in mirrors. The definition given is that the object distance is negative when the incoming light and object are on opposite sides of the mirror. However, this seems to contradict the possibility of creating an image. A suggested resource for clarification is a website on optics and sign convention.
  • #1
C. Long
10
0
We are finishing up light and I'm a little confused on when the object distance would be negative when we are talking about mirrors and not lenses. The definition we were given is that the object distance is negative if the incoming light is on the opposite side of the mirror then the object is. I don't understand how\if that would make any images of the object, wouldn't the mirror be in the way of the incident light?

Thanks for any clarification.
 
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  • #2
I googled sign convention lens mirror and, amongst a lot of hits, http://www.physics.gla.ac.uk/~johannes/optics_lecture/overheads06_1_3_7-1_4_3.pdf . Any use?
 
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  • #3
Thanks. It still looks like there wouldn't be any way the light could create an image if they are on opposite sides of a mirror.
 
  • #4
I haven't read the actual passage that you are quoting from. Are you sure it isn't talking of the image being behind the mirror? IS it just a translation problem?
 
  • #5
I can understand how the image distance can be positive or negative, I just don't see any instance when the object distance would be considered negative and you still get any kind of image. If the physical object is on one side of the mirror and the incident rays are coming from the other, then that tells me there would be no image formed real or virtual.
 

1. How does the object distance affect the image produced by mirrors and lenses?

The object distance, or the distance between the object and the mirror or lens, affects the size and orientation of the image produced. In mirrors, the image formed is upright and virtual, and its size is equal to the object's size. In lenses, the image formed can be either upright or inverted, and its size can be larger or smaller than the object's size depending on the type of lens used and the object distance.

2. Is the object distance the same for mirrors and lenses?

No, the object distance for mirrors and lenses can vary depending on the type of mirror or lens being used. For flat mirrors, the object distance is equal to the distance between the object and the mirror's surface. For lenses, the object distance is measured from the center of the lens to the object. Additionally, for curved mirrors and lenses, the object distance can vary at different points on the surface.

3. How does the object distance affect the focal length of mirrors and lenses?

The object distance is directly proportional to the focal length of both mirrors and lenses. This means that as the object distance increases, the focal length also increases. This relationship is important when determining the magnification of an image produced by mirrors and lenses.

4. Can the object distance be negative for mirrors and lenses?

Yes, the object distance can be negative for both mirrors and lenses. A negative object distance means that the object is located behind the mirror or lens, on the opposite side of the observer. This is commonly seen in concave mirrors and diverging lenses, where the object distance is negative for objects located within the focal length of the mirror or lens.

5. How does the object distance affect the type of image produced by mirrors and lenses?

The object distance is an important factor in determining the type of image produced by mirrors and lenses. For mirrors, the type of image produced is always virtual and upright, regardless of the object distance. For lenses, the type of image produced can vary depending on the object distance. Objects located beyond the focal length of a converging lens will produce a real and inverted image, while objects located within the focal length will produce a virtual and upright image.

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