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

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  • Опубліковано 13 гру 2024

КОМЕНТАРІ • 54

  • @vedanshisingh6248
    @vedanshisingh6248 3 роки тому +86

    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.

  • @NI-rz9ls
    @NI-rz9ls 2 місяці тому +4

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

  • @wormh777
    @wormh777 Рік тому +9

    REAL PHYSICS TEACHER NO CAP ONLY FACTS

  • @sindobrandnew
    @sindobrandnew 11 місяців тому

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

  • @shibaneethakur5035
    @shibaneethakur5035 2 роки тому +7

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

  • @dotman7791
    @dotman7791 3 роки тому +18

    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.

  • @JasonFrench-p2y
    @JasonFrench-p2y Рік тому +1

    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.

  • @shivamprakash6412
    @shivamprakash6412 2 роки тому +2

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

  • @bbhoo4343
    @bbhoo4343 3 роки тому +3

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

  • @jayanth.vjambaldinni653
    @jayanth.vjambaldinni653 Рік тому

    Love your attitude and enthusiasm bro keep it up

  • @NiharikaAChirayil
    @NiharikaAChirayil 7 місяців тому

    Thanks for the video sir!

  • @RaviKumar-sw8dh
    @RaviKumar-sw8dh 3 роки тому +1

    Sir please complete 12 physics syllabus as soon as possible

  • @rofidaahmed4725
    @rofidaahmed4725 Рік тому

    Great!!🥺✨️

  • @lokeshnathsardar1886
    @lokeshnathsardar1886 Рік тому

    Very helpful

  • @lipikalipi6089
    @lipikalipi6089 2 роки тому

    Thank you 🥰

  • @saimaqadeer5898
    @saimaqadeer5898 Рік тому +1

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

    • @Slovenija_patriot
      @Slovenija_patriot 5 місяців тому

      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.

  • @factsss7
    @factsss7 3 роки тому +1

    Thankyou so much sir

  • @ajeeda-hk
    @ajeeda-hk 2 місяці тому

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

    • @ayerhsra23
      @ayerhsra23 2 місяці тому

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

  • @sehreenhafiz4540
    @sehreenhafiz4540 3 роки тому +1

    amazing

  • @paloosalama
    @paloosalama 2 роки тому +1

    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
      @wilsonsamuel6262 Рік тому

      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
      @Slovenija_patriot 5 місяців тому

      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.

  • @tsew1ng
    @tsew1ng Рік тому

    Godlike.

  • @shourabhjamwal599
    @shourabhjamwal599 3 роки тому

    so helpful

  • @AmnaMohammed-l5v
    @AmnaMohammed-l5v Рік тому

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

  • @mohfa1806
    @mohfa1806 Рік тому

    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
    @romario21 3 місяці тому

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

  • @honestman276
    @honestman276 Рік тому

    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.

  • @lakindutheekshana9474
    @lakindutheekshana9474 3 роки тому

    Plz explain with numbers.

  • @JCLMINING
    @JCLMINING 2 роки тому

    Excellent. Thanks.

  • @AmnaMohammed-l5v
    @AmnaMohammed-l5v Рік тому

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

  • @chaudharymujeeb3687
    @chaudharymujeeb3687 2 роки тому

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

    • @ishan_agrawal
      @ishan_agrawal Рік тому

      Differentiate kiya hai
      Sin ka differentiation cos hota hai

  • @ai_talks-l7k
    @ai_talks-l7k 2 місяці тому

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

  • @Arpan2004.1
    @Arpan2004.1 Рік тому

    Why voltage is lesser than current ?

    • @Slovenija_patriot
      @Slovenija_patriot 5 місяців тому

      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.

  • @dual123456789
    @dual123456789 3 роки тому +1

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

    • @Slovenija_patriot
      @Slovenija_patriot 5 місяців тому

      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.

  • @SAURABHKUMAR-oy3nh
    @SAURABHKUMAR-oy3nh 8 місяців тому +1

    Sir please hindi me padhya kijiye

  • @vivekgupta3692
    @vivekgupta3692 3 роки тому +1

    First Comment 😂

  • @Davisthemagnate
    @Davisthemagnate Рік тому

    I don't still understand

  • @nilotpolbarman3162
    @nilotpolbarman3162 2 роки тому +1

    I think u gyz don't know alakh sir

  • @balamphrangmarbaniang9837
    @balamphrangmarbaniang9837 Рік тому

    Thank you so much sir

  • @mohfa1806
    @mohfa1806 Рік тому

    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
      @Slovenija_patriot 5 місяців тому

      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.