AC voltage across a capacitor (derivation) | Alternating currents | Physics | Khan Academy

[@vedanshisingh6248]

This is the channel where someone actually teaches physics. I am in class 12 and I always have a hard time understanding physics conceptually as others just teach math. There are other channels also but to understand concepts to the spleen, this one is gold. This channel is definitely underrated. Thank you so much, sir. You made our lives so much easier.

[@naveensundar4765]

Agreed

[@achievedbigiasasi1333]

100 %

[@yogisiddharth6704]

YES

[@NI-rz9ls]

6:35 thankyou man, I just stumbled upon this problem with 'me' in midst of an exam and I was like how???😅😂

[@wormh777]

REAL PHYSICS TEACHER NO CAP ONLY FACTS

[@sindobrandnew]

8:09 Most instructors just skip to here so thank you for explaining further extra steps.

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Your voice express your curiosity towards physics.....🤩🤩🤩🤩🤩 Teaching style encourage me to watch your videos ahead

[@dotman7791]

You are the only living legend among all the physics teachers in India. You deserve to be awarded Bharat Ratna or Nobel prize for teaching physics correctly.

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[@JasonFrench-p2y]

Just watched this video after watching 3 other videos trying to explain the same thing... I rarely leave comments, but this explanation made things MUCH clearer to me that I felt compelled to applaud. Well done and thank you! Will definitely watch more of your videos.

[@bbhoo4343]

omg your teaching was absolutely beautiful sir! Thanks a lot!!

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I think the teachers should take lesson from this channel the way of teaching and explaining concepts like this.🙏🙏🙏

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[@ajeeda-hk]

4:53 i don't understand how sin becomes cos and why omega pops out

[@ayerhsra23]

Cuz the derivative of sin wt = derivative of sin wt × derivative of wt = coswt × w

[@RaviKumar-sw8dh]

Sir please complete 12 physics syllabus as soon as possible

[@NiharikaAChirayil]

Thanks for the video sir!

[@rofidaahmed4725]

Great!!🥺✨️

[@lipikalipi6089]

Thank you 🥰

[@lokeshnathsardar1886]

Very helpful

[@factsss7]

Thankyou so much sir

[@paloosalama]

Thanks for your effort! I have a question: how is it possible in initial moment of time when V=0, I=max? In this point voltage difference is zero, so the capacitor wouldn't "know" how great it would be to "calculate" I max. Really really looking forward for your answer, thanks.

[@wilsonsamuel6262]

Capacitor is a device for storing electrical energy . My point is when voltage [ potential difference ] is zero the potential difference in the whole circuit is same which is v = 0 this can only happen if the Capacitor is charged to its extent and at the very stage to get discharged. Hence it holds the maximum current

[@Slovenija_patriot]

You shouldn't look at magnitude of voltage but rather how fast the voltage of capacitor is changing because current of capacitor is dependent on how fast the voltage is changing. You have equation ic = C * dv/dt which tells you that current is at maximum when voltage is changing the fastest (when the line on graph is the sharpest which happens across 0V). Because if you want faster change in voltage you need more current = more charge. When voltage is at maximum current is at 0 because at that point voltage doesn't rise anymore and the change in voltage is 0. It's quite logical if you think about it.

[@saimaqadeer5898]

If voltage across capacitor is same as voltage generated then how the current would flow ???

[@Slovenija_patriot]

No you have to look at it other way. The voltage source creates current that charges capacitor to the voltage of the source. But voltage of source is constantly changing which means that capacitor must be also constantly charging and discharging with current. You would be correct if we were talking about DC circuits because in DC circuits capacitor charges to source voltage and then there is no more current because voltage isn't changing like in AC.

[@sehreenhafiz4540]

amazing

[@shourabhjamwal599]

so helpful

[@mohfa1806]

Thank you for your great educational lessons I have question please : i am confused how we can write : Vs= Vc knowing that the capacitor "gradualy" raise its voltage and doesnt respond instantaneously with the voltage source ! , why we are ignoring this fact and treating capacitor as if it is a resistor ? Thank you in advance

[@romario21]

what program have you used to create this presentation,please?

[@AmnaMohammed-l5v]

How does alternating current arise the applied voltage equal to the voltage inside the coil and opposite in direction? And why

[@honestman276]

Thanks from Bangladesh. But sometimes a mysterious causes in your voice deforms the sound issued from your mouth. Don't mind. I am grateful to you. Thanks again from Bangladesh.

[@StrongerEveryday13]

Can you provide your videos in hindi language?

[@KhanAcademyIndiaEnglish]

Ye lijiye! www.youtube.com/@khanacademyindia

[@AmnaMohammed-l5v]

How does alternating current arise when the applied voltage is equal in magnitude to the voltage inside the coil and opposite in direction?!

[@tsew1ng]

Godlike.

[@chaudharymujeeb3687]

Why we change the function from sin to cos?????

[@ishan_agrawal]

Differentiate kiya hai Sin ka differentiation cos hota hai

[@lakindutheekshana9474]

Plz explain with numbers.

[@dual123456789]

In the graph the peak value of current is shown greater than that of voltage is this correct?

[@Slovenija_patriot]

You can't compare voltage and current on the graph by their height because they are measured in different units. Current is measured in Ampers and voltage is measured in Volts. You could have voltage bigger than current if you choosed so.

[@Arpan2004.1]

Why voltage is lesser than current ?

[@Slovenija_patriot]

You can't compare voltage and current on the graph by their height because they are measured in different units. Current is measured in Ampers and voltage is measured in Volts. You could have voltage bigger than current if you choosed so.

[@JCLMINING]

Excellent. Thanks.

[@Hmm_Nation]

how does current be there.? its a capacitor . someone pls explain

[@SAURABHKUMAR-oy3nh]

Sir please hindi me padhya kijiye

[@Davisthemagnate]

I don't still understand

[@vivekgupta3692]

First Comment 😂

[@nilotpolbarman3162]

I think u gyz don't know alakh sir

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shut it

[@person17_ro]

Khan Academy >>>>

[@balamphrangmarbaniang9837]

Thank you so much sir

[@mohfa1806]

Thank you for your great educational lessons I have question please : i am confused how we can write : Vs = Vc knowing that the capacitor "gradualy" raise its voltage and doesnt respond instantaneously with the voltage source ! , why we are ignoring this fact and treating capacitor as if it is a resistor ? Thank you in advance

[@Slovenija_patriot]

In video he put capacitor directly across source which means that the voltage of source must be equal to voltage of capacitor. The current adjusts itself so that this can happen. When voltages is changing the fastest (the sharpest line is across 0) the current is at it's maximum and when voltage isn't changing the current is 0A. It's because of the equation: ic=C*dv/dt which tells you that current is at maximum when voltage across capacitor changes the fastest.