Multiple lens systems | Geometric optics | Physics | Khan Academy
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- Опубликовано: 5 июл 2014
- Some examples of using the thin lens equation with multiple lenses. Created by David SantoPietro.
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This video was the best explanation of a multi-lens system I have found thus far.
Would you guys consider doing more complex optics videos specifically covering Gaussian lens systems??
I love Khan Academy! Thank you!
This guy is good. Khan academy needs more people like him.
thank you! life saver
What a wonderful video! Excellent explanation, I would rate this as A+ standard
Thanks, it's very clear and easy to follow along!
thank you so very much for this explanaiton, it really helps a lot ! (also your voice is really nice to listen to :D)
Thank you so much! You are an amazing teacher.
Thanks it's really helpful
What screen recording software do you use? I would like to know a good one that allows me to pause recording.
Thank you so much Khan academy
For lens 2, How it becomes -6 (di)?
What if the 2nd lens is closer to the 1st lens than the 1st lens' focal length? e.g. if the 2nd convex lens is 2.5 cm away from the 1st convex lens and both have focal lengths of 5 cm?
if di is negative (-6cm from the calculation) shouldn't it be on the same side of the eye based on your explanation? I get that it will be on the left side of the second lens because the focal length is -10 cm, but following your explanation made me little bit confused.
when it comes to image distance, if the number is positive the image is on the same side as the eye (between the lens and the eye) and if the answer is negative then the image on the other side of the lens.
Excellent lecture ❤️❤️❤️❤️❤️
love you khan academy , you are the best of best , thanks and keep making such aha moment videos😉😉😉
OMG I UNDERSTOOD!!!
Is the "object" for the second lens not a "virtual object"? And, should the "Object distance" in that case not be negative?
Hi you explained nicely but 2:43 it u (object distance ) will be negative because according to sign convention of lenses, all distances are taken to be positive when they are in the direction of the incident ray.
the formula he used is different. he used mirror formla
What do if the image distance of convex lens is greater than distance BTW lenses
NIce.
How did you add those fractions
Can you do a 3, 4, 5 lense?
awesome
Thank you so much
Hi theacher, can I use these formuls in this video in any case.
In this exercise what gain we got in this composition lens where magnification is reduced to ,2 times?
tysm u saved my final exam for tomorrow
How about image created by first lens is behind the second lens?
u saved me
6:20 on the concave lens that image distance would be positive (sign convention) you may Google and check
you are wrong. whether the image distance is positive or negative is based on your calculations via the lens formula.
@@sme_station5179 he cant be wrong he is Asian
You're the best 😭
at 8:45 in the "Thin lens equation and problem solving" video, David, says " -di = non inverted and +di = inverted; however, in this video at 12:16, he draws the image as inverted, even though he got -di. Why is this? Is this just a "special case" with multiple lenses?
Inverted refers to the object image, in the second lens, the "object" which is Image 1 is already upside down. Since di is negative and M becomes positive its non inverted, aka meaning Image 1 (is not inverted, stays the same as it is which is underneath/inverted).
If di was positive, you would invert image 1, inverting an image upside down, would make it right side up.
nicee
M should be equals to positive v/u, not negative?? Please correct me if I was wrong...
no it should not be equal to v/u as you take negative v for the equation.
charis teoh yi en it is positive for mirror formula but it is a lens so it will be negative
how does that adding fractions work? I'm not getting those numbers for Di at all
Mohammad Hussain same here
Find the LCM. between d denominators, then u divide the LCM by the denominators and multiply by numerator.
Magnification does not tell the exact length of the object right?
on the second lens, since m>0, can you explain to me why it is not upright and why inverted @__@
+gidyawn chew It was obviously a mistake...
It's because the second lens treats the first lens' d_i point as it's object. The image made by the first lens is inverted, and the second lens does not "invert it back" because it's m is positive :)
Because the second lens isn't "seeing" the subject, it only sees i1, which is upside down. Lens 2's magnification is positive, so it doesn't flip it again, so it stays inverted.
Whats his name??
when u said 'its gonna make an image of an image i laughed so hard . but thanks man aved me
❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
omg kmn
How did he get 1/18 for di when 1/12 - 1/36 = - 1/24
Michal Korneev u can't divide denominator directly
I think the answer is -5 cm not 6
i ve senn little so far of but in terms of theory they seam correct however the mathemathics are completly wrong i mean please put a disclamer cause it is really bad and it can induce in error
Power leans scope Objects ma diamond 💎 (bem of leaser)
Galileo Galilei I believe used these two lenses for he's telescope.? i wasn't there at the time so i could be wrong.
thin_lens_formula:
image.distance = focal_length * object.distance / (object.distance - focal_length);
object.distance = focal_length * image.distance / (image.distance - focal_length);
focal_length = image.distance * object.distance / (image.distance + object.distance);
magnification_formula:
magnification = -image.distance / object.distance;
magnification = image.height / object.height;
total_magnification_formula:
for (i = 1; i < total, ++i)
magnification[0] *= magnification[i];
# License: CC BY-SA 4.0 or later, AGPL V3.0 or later #
For the first lens if u, f and v all are positive, then all should be on the same side... BUT THEY'RE NOT ON THE SAME SIDE.
as for convex lenses the focus is on the other side of the object f and u should have opposite signs!!!!!
THAT'S A MISTAKE!!!!!
I also freaked out on my last semester test
Which year?
Sign confused