Potentiometer - calculating internal resistance of a cell | Electricity | Physics | Khan Academy

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  • Опубліковано 15 січ 2025

КОМЕНТАРІ • 90

  • @black_jack_meghav
    @black_jack_meghav 3 роки тому +74

    I love the vibes in the comment section , where everyone is literally overwhelmed by the joy of understanding . THANKS KHAN ACADEMY!

  • @jyotisingh4109
    @jyotisingh4109 Рік тому +11

    When says things like " don't remember the formulas concept is everything" my heart goes.😩😍🛐
    Its so opposite of what I've heard from my teachers

  • @Khyatii_Verma
    @Khyatii_Verma 3 роки тому +12

    the amazing line:how many formulas will u remember?concept is all that matters.true.

  • @noone12323
    @noone12323 7 місяців тому +4

    I don't know if you'll ever read this or not, but I just want to say that you are excellent. I am literally watching this while laying on my bed, at 1 am. I am frustrated and very tired but still, with like half my consciousness, I understood the topic. 😅😂. I am planning to pull off an all nighter as my practical exam is scheduled tomorrow. I'll try my best to study as much as possible.

  • @manojlords7831
    @manojlords7831 4 роки тому +10

    Ur explainnation is very awesome bro for every video

  • @shreyaagarwal798
    @shreyaagarwal798 3 роки тому +4

    i like khan academy more than any other learning platforms ... they are just amazing

  • @mayankjangid1543
    @mayankjangid1543 3 роки тому +11

    I have no words to say!
    Thankyou so much!

  • @daphinekarungi9794
    @daphinekarungi9794 2 роки тому +2

    you have saved a ugandan girl from failing God bless you

  • @rishi9335
    @rishi9335 2 роки тому +5

    I want Mahesh sir to cover the whole class 12&11 syllabus of physics, Oly by Mahesh Sir

  • @prayashpreet8693
    @prayashpreet8693 3 роки тому +6

    Amazing practical explanation with good mind exercise.❤️❤️❤️❤️thank u so much for these 🙏.

  • @endlesslearning26
    @endlesslearning26 3 роки тому +3

    your explanation are the best available on the whole internet ,
    you are awesome

  • @kabandajamir9844
    @kabandajamir9844 2 роки тому +3

    The world's best teacher thanks

  • @gagans7180
    @gagans7180 3 роки тому +4

    thank you so much sir , it cleared the concepts which were long pending

  • @harsh009
    @harsh009 3 роки тому +5

    Best explanation of potentiometer on UA-cam dhanyawad (in English='thankyou')

  • @VardhanMittal
    @VardhanMittal 2 роки тому +3

    awesome lecture you made the things damn easy !

  • @sapphireblue9209
    @sapphireblue9209 4 роки тому +20

    Thank you so much for this explanation! Your videos have clarified many topics and derivations for me. Can't believe I didn't watch them before haha. Keep up the good work!

  • @theultimatebeast6597
    @theultimatebeast6597 3 роки тому +1

    Khan academy is the best

  • @riyajain3476
    @riyajain3476 3 роки тому +3

    Concept Matter!!:) Good One.

    • @vinitgaikwad8127
      @vinitgaikwad8127 3 роки тому +1

      lmao seems like we have same roll no. hahahaha

  • @bandanasuar9598
    @bandanasuar9598 4 роки тому +3

    Kudos to you sir

  • @hangkertzy9722
    @hangkertzy9722 4 роки тому +2

    i love your explanation!!

  • @nehasaini5517
    @nehasaini5517 2 роки тому +1

    Really helpful😃. Thank you sir 🙏🙏

  • @anzarhasan2349
    @anzarhasan2349 4 роки тому +3

    Sir, please cover Electrostatic potential. Please

  • @akshayaraja1180
    @akshayaraja1180 14 днів тому

    Wonderful concept breaking expln

  • @schoolboybt5563
    @schoolboybt5563 2 роки тому +2

    It make me cry , I was frustrated . thanks a lot. Even my eng is poor but i understand well.✌️

  • @NEETard.
    @NEETard. Рік тому

    Epic explaination and visualisation

  • @anandapatmanabhansu
    @anandapatmanabhansu Рік тому

    Thankyou so much sir❤❤❤❤❤❤♥♥♥

  • @keerthanasatheesh9639
    @keerthanasatheesh9639 3 роки тому +1

    Thank you so much sir

  • @loudulalit4291
    @loudulalit4291 3 роки тому +3

    Mind blowing explanation sir 🙏🙏🙏
    I just fall in love with u r teaching method. ❤❤
    Thanks sir

    • @Just_Moh_it
      @Just_Moh_it 3 роки тому +1

      Mind blowing Name 🙏🙏🙏
      I just fall in love with u r Name. ❤❤
      Thanks LL 🤣

    • @loudulalit4291
      @loudulalit4291 3 роки тому

      @@Just_Moh_it thanks sir

  • @akihari2468
    @akihari2468 Рік тому

    Thank you

  • @Prachita516
    @Prachita516 3 роки тому

    Thank you for the feel of concept

  • @osimothobi2972
    @osimothobi2972 3 роки тому

    Wow... This guy is goooddd. 👏 👏 👏

  • @Naveen_1176
    @Naveen_1176 Рік тому

    Thank you so much❤

  • @mangakhoon4517go
    @mangakhoon4517go 8 місяців тому

    Mahesh: "I am not gonna cheat"
    Me: "You can't stop me though"

  • @elizabethelson1124
    @elizabethelson1124 3 роки тому

    Superb 👍👍👌👌

  • @vivekgupta3692
    @vivekgupta3692 2 роки тому +13

    *_Summary Of The Video :-_*
    *Potentiometer*
    * We use a voltmeter to measure the potential difference (Voltage) but it does not give us accurate value.
    Because it draw some ammount of current from the circuit. Which can change the value of Voltage as well.
    * We can measure the accurate value of Voltage by using a _Potentiometer_.
    *Principle Of Potentiometer -* The principle of a potentiometer is that the potential dropped across a segment of a wire of uniform cross-section carrying a constant current is directly proportional to its length.
    *Wire Used In Potentiometer -* Generally alloys like constantan or manganin are used as potentiometer wire because they posses high specific resistance and low temperature coefficient
    *Null Point or Balancing Length Of The Potentiometer -* The balancing point or null point of the potentiometer is the point on the slide wire when the galvanometer shows zero deflection.
    *Primary Circuit & Secondary Circuit -* primary circuit consists of a secondary cell( driver cell). and a secondary circuit is the one in which the primary cell whose emf is to be determined is connected.
    *Potential Gradient -* Potential drop per unit length of the wire is known as potential gradient.
    *Sensitivity Of Potentiometer -* Sensitivity of Potentiometer means the smallest potential difference that can be measured by using it and this can be achieved by decreasing the potential gradient by increasing the length of the wire.

    • @Nishantsingh-bq1ml
      @Nishantsingh-bq1ml Рік тому

      how many time you spent on making it😂

    • @sajidhajiffrey310
      @sajidhajiffrey310 Рік тому

      ​@@Nishantsingh-bq1mllts actually OK, cause for someone somewhere this might help in understanding certain definitions

  • @jueemahajan8537
    @jueemahajan8537 10 місяців тому

    perfect

  • @hasarudamsara8684
    @hasarudamsara8684 2 місяці тому

    Bro got +999999 aura fr. Thanks

  • @jannatun-naimamedha173
    @jannatun-naimamedha173 2 роки тому

    Salute man

  • @nish9421
    @nish9421 Рік тому

    Wow...! 🥺🥺🥺💗💗

  • @niranjan7457
    @niranjan7457 3 роки тому +1

    Sir at 10:46, why didn't the Galvanometer stay at 0? Why did the Voltage drop when Current was passed through it? Please clarify sir

    • @KhanAcademyIndiaEnglish
      @KhanAcademyIndiaEnglish  3 роки тому +5

      This is clarified in our previous videos on EMF and cells. In short, if you have a 9V battery, it means a coulomb of charge gains 9J of energy as it gets pushed from lower to higher terminal. But, due to internal resistance, some of that energy is converted to heat, as a result the net energy gained will be less than 9. This net energy gained is the potential difference across the cell. The more current we draw, the faster the coulomb moves, the more energy is lost to the resistance, the smaller net energy gained, and hence smaller the p.d. across the cell!

    • @niranjan7457
      @niranjan7457 3 роки тому

      @@KhanAcademyIndiaEnglish Thank you so much sir!!! 🙏🙏🙏

  • @mayankjangid1543
    @mayankjangid1543 3 роки тому +4

    From where do you study all these things?

    • @madman0016
      @madman0016 3 роки тому +11

      Clarity of this level is only attained by studying not for marks but for curiosity
      At that point it doesnt really matter where they study from.

    • @samreeves3029
      @samreeves3029 3 роки тому

      @@madman0016 facts mate. 👍🏽

  • @cypherfps3695
    @cypherfps3695 2 роки тому

    6:06 how to measure voltage without drawing current. Does the measuring device work without current. Please help

  • @daphinekarungi9794
    @daphinekarungi9794 2 роки тому

    you are sooo gooddddd

  • @pavanKumar-hm7on
    @pavanKumar-hm7on 3 роки тому

    Aswome explanation opopoop

  • @aanyakashyap_
    @aanyakashyap_ 4 роки тому +4

    damm!!!! your accent soo cool ...........

  • @anshik.k.t
    @anshik.k.t 3 роки тому +1

    When I am measuring emf without bulb ... There is still a internal resistance... so isn't that gonna draw some current and hence disturb reading?

  • @romanpunk2396
    @romanpunk2396 3 роки тому

    Love u bro

  • @NEETard.
    @NEETard. Рік тому

    Pta nahi aisi dangerous situations mein apne aap Khan academy meri help karne kaise aage aa jata hai

  • @sashwatyo1293
    @sashwatyo1293 4 роки тому +1

    Sir one doubt , shouldn’t the voltage of battery be E-ir?

    • @KhanAcademyIndiaEnglish
      @KhanAcademyIndiaEnglish  4 роки тому +2

      That's true as well, but we wanted a relation connecting the EMF and the external resistor, since its value is directly known.

    • @sashwatyo1293
      @sashwatyo1293 4 роки тому

      @@KhanAcademyIndiaEnglish Oh okay sir got it. But sir I got another doubt- why is I=E/(R+r) ,E isn’t the terminal voltage,sir.

    • @KhanAcademyIndiaEnglish
      @KhanAcademyIndiaEnglish  4 роки тому +2

      @@sashwatyo1293 Maybe go through our videos on cells and EMF?

    • @sashwatyo1293
      @sashwatyo1293 4 роки тому

      @@KhanAcademyIndiaEnglish yes sir sure sir...actually I have done that Concept once , but I have forgotten most of them over the year......Thanks sir ...;))

  • @kiranbhat4902
    @kiranbhat4902 4 роки тому +2

    Sir is the magnitude of charge of an electron -1.6 * 10^-19C or 1.6*10^-19 C ? How can 1C of charge contain 6.25 times 10^18 electrons? If 6.25 *10^18C
    Move to right can we say 1C of charge moves to left? Please please answer my doubts I have these doubts from a few years and they aren't clarified....🙏🙏🙏

    • @manojmaheshwari4055
      @manojmaheshwari4055 4 роки тому

      Charge on an electron is -1.6 *10^-¹⁹ C but the magnitude willl be positive of that value . And through milikans oil drop experiment we found that value , and if there are n electrons the the charge would be n times that value (e=1.6*10-¹⁹) . So q=ne . So if there is 1C of charge n=q/e so 1C/ 1.6*10-¹⁹ which will be equal to 6.25 *10¹⁸ electrons. If ther was 6.25 times 10^18 C of charge divide that by "e" and u will get no of electrons in that amount of charge. We generally use conventional current where positive charges flow but really not , electrons ( negative charges ) are actually flowing from negative terminal to positive terminal) but between 80-90's they used to follow that positive charges flow . So we r till now following that convention that's y it is called as conventional current . So mathematically , a positive charge flowing in a direction is equal to negative charge flowing in the opposite direction. Hope u get that

    • @kiranbhat4902
      @kiranbhat4902 4 роки тому

      @@manojmaheshwari4055 superb 👏👏👏

    • @kiranbhat4902
      @kiranbhat4902 4 роки тому

      @@manojmaheshwari4055 thank you

    • @manojmaheshwari4055
      @manojmaheshwari4055 4 роки тому

      @@kiranbhat4902 I'm happy to help you kiran🙏🏻🙏🏻

  • @vijayvittalrao4197
    @vijayvittalrao4197 11 місяців тому

    🎉

  • @subramanianloganathan8696
    @subramanianloganathan8696 3 роки тому

    Sir why do we have to get rid of the bulb while we are calculating the emf of the battery?

    • @tiredcat6653
      @tiredcat6653 3 роки тому

      Because with bulb the voltage that potentiometer measure is terminal voltage and without bulb the voltage that potentiometer measures is emf

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

    • @nandhinir9747
      @nandhinir9747 4 роки тому

      Just practice the questions bro from question bank....

  • @Sanoui
    @Sanoui 10 місяців тому

    Thank you

  • @Keneethgurung
    @Keneethgurung 2 роки тому

    Thank you so much sir

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @CC-rx7kt
    @CC-rx7kt 2 роки тому

    Thank u so much sir.

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced

  • @krishnaniti6208
    @krishnaniti6208 4 роки тому +1

    please tell us the best books for iit jee advanced