Any tutorial on optic physics using 2 lenses (+ and -)

In summary, when learning about mirrors and lenses, it is important to establish the sides of the object and the mirror/lens. For mirrors, the sign convention is positive for objects in front and negative for objects behind. For lenses, the convention depends on whether it is a converging or diverging lens, with the exception of the image distance. This knowledge will help in understanding focal length, radius of curvature, image distance, and object distance.
  • #1
EternityMech
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the title pretty much. thanks.
 
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  • #2
Not really a tutorial but I learned the conventions for mirrors first then translated them into the ones for lenses.

Firstly and most importantly, establish what sides of the mirror/lens are in front and behind.

For mirrors, it's simply identifying whether or not it's in front or behind the mirror. If it's in front, it's positive ( + ). If it's behind, it's negative ( - ). This the rule for focal length, radius of curvature, image distance, and object distance. Easy.

Now once you've got that down, for lenses all you have to do is identify whether its a converging or diverging lens. If it's a converging LENS you use all the sign conventions for a converging MIRROR, *EXCEPT* for the image distance. The same applies to diverging lenses (Again, *EXCEPT* image distance - i.e. image distance is negative if image is in front of lens)

Hope this is helpful.

Steve
 

Related to Any tutorial on optic physics using 2 lenses (+ and -)

1. How do two lenses with opposite signs affect the optics in a system?

The sign of a lens refers to its curvature, with a positive sign indicating a convex shape and a negative sign indicating a concave shape. When two lenses with opposite signs are used in a system, they can either cancel each other out or work together to magnify or reduce the image.

2. Can you explain the concept of focal length and how it relates to two lenses?

Focal length is the distance between the lens and the point where light rays converge to form an image. In a system with two lenses, the focal length of the first lens affects the focal length of the second lens. The combined focal length of the two lenses determines the magnification or reduction of the image.

3. How does the distance between two lenses affect the optics in a system?

The distance between two lenses, also known as the lens separation, plays a crucial role in determining the behavior of light rays passing through the system. The closer the lenses are to each other, the more interaction and magnification or reduction of the image will occur. On the other hand, a larger lens separation may result in a weaker or no image formation.

4. Can you provide an example of a real-life application of using two lenses with opposite signs?

One common application is in eyeglasses, where a convex lens is used to correct farsightedness (positive sign) and a concave lens is used to correct nearsightedness (negative sign). The combination of these two lenses allows for clearer vision by adjusting the focal length of the eye's lens system.

5. What is the difference between using two lenses with opposite signs and using a single lens with two sides of different curvatures?

Using two lenses with opposite signs allows for more control over the magnification or reduction of the image by adjusting the distance between the lenses. On the other hand, a single lens with two sides of different curvatures, also known as a meniscus lens, has a fixed focal length and cannot be adjusted as easily as two separate lenses.

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