Derivation of the mirror equation | Geometric optics | Physics | Khan Academy

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In this video David derives the mirror equation and magnification equation. Created by David SantoPietro.
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[@romarssieverything9667]

Wow .my teacher couldn't make me understand this in 150 minutes.And u did it in about 14 minutes.Thnx a lot.I would be glad now if this derivation comes in the exam.

[@princevegeta5907]

At 8:57, this doesn't make a complete triangle and there is little uncertainty i.e image height near the tangent is slightly longer than the actual image height.
Then, won't the mirror equation give approximate answers rather than actual values?

[@yashuppot3214]

Yes the equation itself is an approximation

[@matthewjames8127]

This is a neat approach instead of proving the mirror equation with Euclid's exterior angle theorem and small angle approximations.

[@silviamayo2993]

It's so satisfying that he uses that tool to draw straight lines.

[@rupjyotidas3091]

But my book shows that the object distance will always be negative if it is in front of the concavemirror and will always be positive if it is behind the convex mirror

[@shabarish2727]

take any direction you want
just all other directions should be taken in the same convention.
Object distance negative then so be it , just adjust others

[@zafferabassnaik]

It is for convex mirror.

[@scotttallec584]

No always negative in my class, You just have to indicate eventually what frame of reference you're using on a diagram. I believe Khan even stated that algebraically we have left to right is positive and down to up is positive.

[@resendylldcruz1137]

Guys do we have to make it with measurements or without measurements

[@lucasfreire1090]

I didn't find this video to be accurate, because the object height is being measured from the vertex of the mirror and not from the point where the yellow ray of light is reflecting

[@Fidonese]

This video was an absolute lifesaver... Thank you so much.

[@chie8466]

Thanks! ❤❤

[@ASHOKKUMAR-cx4ey]

In indian textbooks the direction convention is just opposite . We consider object distance negative

[@juankim9581]

Love your videos!!!
They're absolute quality

[@RyanLynch1]

or angle angle angle triangle similarity

[@lemonpooh1764]

thank you soooooo much

[@seamusfing]

i love you

[@BBTAatharshV]

A good one ...🤞🏻✌🏻

[@goamhobala]

Dioooooooooooo

[@AldeyWP]

Beautiful!

[@caputlp1340]

Isn't there something wrong with the last triangle? I meen how can you assume it is a right triangle? Is it just an approximation?
By the way great video 👌

[@burninhell4448]

Yes, it is just an approximation.

[@karmapolice3335]

ah man you complicated this so much...