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What kind of lens would you use for each and why? This isn't registering with me.
Thanks
Thanks
What kind of lens would you use for each and why? This isn't registering with me.
Thanks
Awesome, got it, thanks a bunch.
Congrats on the MD/PhD acceptance
Sleepy's explanation is excellent.
I want to add a different approach to the problem that may also help. If you are one who visualizes ray diagrams well, then this method should help.
With a diverging lens, some of the virtual rays initiate from the virtual focal point, and thus intersect other rays between the f and lens. This means that the image is ALWAYS found between the lens and the virtual focal point. Such an image will always be near to the lens, relative to the position of the object. For someone who is nearsighted, a lens that can take a faraway object and generate a near image will be the ideal corrective lens.
With a converging lens when the object is inside the focal length, a virtual image is generated farther from the lens than the object. In other word, a converging lens can take a near object and generate a faraway image. Such an image will always be far from the lens, relative to the position of the object. For someone who is farsighted, a lens that can take a near object and generate a faraway image will be the ideal corrective lens.
While Sleepy's explanation is better and based on tangible fundamental information, this method can prove useful for people who are good at visualizing ray diagrams. It's quite fast if you can picture it.
Sleepy's explanation is excellent.
I want to add a different approach to the problem that may also help. If you are one who visualizes ray diagrams well, then this method should help.
With a diverging lens, some of the virtual rays initiate from the virtual focal point, and thus intersect other rays between the f and lens. This means that the image is ALWAYS found between the lens and the virtual focal point. Such an image will always be near to the lens, relative to the position of the object. For someone who is nearsighted, a lens that can take a faraway object and generate a near image will be the ideal corrective lens.
With a converging lens when the object is inside the focal length, a virtual image is generated farther from the lens than the object. In other word, a converging lens can take a near object and generate a faraway image. Such an image will always be far from the lens, relative to the position of the object. For someone who is farsighted, a lens that can take a near object and generate a faraway image will be the ideal corrective lens.
While Sleepy's explanation is better and based on tangible fundamental information, this method can prove useful for people who are good at visualizing ray diagrams. It's quite fast if you can picture it.
This.k, for nearsightedness (myopia), you use a diverging lens. for farsightedness (hyperopia), you use a converging lens.
here's why:
in a normal eye, the lens of the eye focuses the incoming light so that the image is formed exactly on the retina (since the retina is the part of your eye that detects light). if the image forms in front of the retina, or behind the retina, then you have a problem, and the image will be blurry since it is not focused.
in myopia, the image forms in front of the retina (so basically, the lens focuses the light to some point before it gets to the retina). To correct this, we need to make the image form a little later. Since diverging lenses "spread out" the light (as opposed to focusing the light), they can be used to correct myopia. In other words, say the retina is 2 cm away from the lens of your eye, but the lens of your eye makes the image form at 1.8 cm away. The diverging lens will diverge the image so that it doesn't focus until it has traveled 2 cm from your eye's lens.
in hyperopia, the image forms behind the retina. So we need to have the image form a bit earlier. For example, if we again say that the retina is 2 cm away from your eye's lens, and you're hyperopic so the image forms at 2.2 cm, basically your lens isn't focusing well enough. So you add a converging lens, which focuses the light so that it will form the image at 2 cm instead of 2.2 cm.