Convex lenses | Geometric optics | Physics | Khan Academy

Convex Lenses. Created by Sal Khan.

Physics on Khan Academy: Physics is the study of the basic principles that govern the physical world around us. We'll start by looking at motion itself. Then, we'll learn about forces, momentum, energy, and other concepts in lots of different physical situations. To get the most out of physics, you'll need a solid understanding of algebra and a basic understanding of trigonometry.

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[FilezillaDownload]

Thanks Khan for posting these free educational videos, you're doing a wonderful service.

[tmath]

the car analogy is like the greatest thing i have heard. it makes perfect sense now.

[jalapenosmepeno]

Man, I love your work. you have made over a thousand videos just to help us learn. You have a good heart, thank you :) I appreciate it.

[BenjaminBorgbeno]

light in a vacuum has a refractive index of 1. In Denser media(transparent objects), light travels slower. The speed of light is differnent in water that hhas a refractive index of 1.47 than in air with a refractive index of 1. Using the mita equation, one can find the constant- speed of light in air/speed of light in water. Hope this helped

[youn]

1 hour class and the whole class doesn’t get anything.
Khan saves the day again

[MohanRaj]

He might be getting paid. But that was not the original plan. In fact, he had no plan at all. He just started this on his own, spending his own money and time, just to help students. Only later, when it became a real tangible success the corporation started to give money. So, for a selfless person, he deserves this. There is a big difference between those people who make things with money in mind and those who make things for bettering humanity and then later get recognition and then get paid.

[PearlLikesBirds]

I am really thankful for your videos...Physics is my favorite subject, but sometimes I can't understand the teacher and I get really stressed out, but then I watch a video of yours and everything gets clear! Thank you so much :)

[Jellgumi]

Your better then my teacher, thank you 🤠👍

[michaelkoles]

1:50 Miller's... it's parabolic-shaped now! :)

[AlphaCrucis]

Wow you're doing optics now? Or is this going to be part of the physics playlist?

[shinuito]

@Rivoluzzjoni i'd think they're close to being on par anyway. they're both really easy and interesting to listen to

[rajeshvelamarthi]

Very useful and informative videos, Thanks to team.

[murat.eraydin]

Hi Khan, I have a question but I dont know how to proceed; say I have a wall (20cm) thick, and I want to transfer light from outer side to inside. outer side looks at the sky, inner side is dark. What I want to achieve is illuminate dark side. Can I do it with two half spherical lenses with f=10cm?

[conn]

i understand how the rays move through the lens, but how come when you look through a magnifying glass, the picture/object is not inverted?

[christophersteyn]

Thats funny because Sal is payed millions of dollars by the Gates Academy to make these videos :P but I still agree with you, it is incredibly selfless to dedicate so much time to teaching people for free.

[xetrius]

Time: 1:36
Quote: "something in which light travels slower."
I thought that the speed of light was always the same?

[Chelsea-gsqj]

Im so confused. When is it a virtual image and when is it a real image?? And I thought he said in the last video that the outer side of the lens was reflective so why is the ray going through?

[ananyasinghable]

my name is khan, and i am not money minded ! :D