When your favorite teacher teaches you in his own channel! When I found you on Khan Academy, I searched for your UA-cam channel. Though there were videos, you weren’t regular. Great to see you uploading lectures regularly. Take love from Bangladesh. ❤️
@@harshad1526 In a conducting material (like a wire), voltage is the same everywhere. So if you have any number of points on a wire connected with nothing in between, they are at the same voltage. Now, imagine three resistors of different resistances connected in parallel. The left side of the resistors are all connected with a wire, so their voltage will be the same, call it V1. Now, their right sides are connected by a wire as well, so their voltages will be the same, call it V2. So, each resistor will have a voltage drop of V2-V1 volts. This applies to any component whether it be batteries, capacitors, inductors, whatever, since voltage is the same throughout any conducting material. (Assume zero resistance)
I can't describe how much you helped me!!! I am a 10th grader and i had the same exact doubt which is in the video and i couldn't get it solved because of which I wasn't able to continue the chapter. I researched everywhere but my doubt was not fully clear. It may seem weird but i literally cried because i couldn't understand anything and find meaning to things and after that i gave up and thought I'll have to accept things to complete my syllabus but as i continued the chapter, I encountered another confusion, which was why does current remain same after passing through a resistor. I searched, watched many videos, didn't understand anything, watched yours, fully understood and then watched this one. You won't believe me you came like a god. I could score full marks by just understanding what's given in the book but i don't study for marks and my brain can't rest if I have a doubt. I have never commented this long on any video Thank you sooo much sir!!!
I am studing electrotechnics at PW (Poland) and i have to truly admit that's (and other videos) the best explenation (especially How circuts really works) i've ever heard. Despite of many bigbrain profesors (it is not an insult) nobody could explain to me these things as clearly as you did. It is a big, increadbly improtant amount of yours work. And it is not just an another courious video like many other videos "something you didnt know", it has big impact how we see the world even if we're not technician. It is our duty as humanity to keep trying understand and describe what we see accordilngy to its profession.
You are amazing bro . I had asked this same question to my school teacher but no one had answer . They also understand my question that electron should have more energy but no one had courage to think in opposite to books text . You are a true teacher .❤
Man, I discovered your channel a few weeks ago and I am addicted to your videos. I have already seen dozens of them. I love how you explain everything in order to understand and not to memorize. You are the best man, greetings from germany
Ok...thanks for these last two videos. Really explanatory. Just one question though. If voltage determines how much current flows through a circuit and how fast, can we say that the voltage drop is experienced across the entire circuit though affected by the resistor alone. The reason I'm asking this is because you said in your previous video that the speed of the electron is affected by the resistance and all the electron pay the price for that resistance in their speed. I don't even know if i am making any sense.
Wow I just found your channel and I am really amazed by your explanations . These are explanations I always looked for. Thank you so much for your work.
Mahesh, I'm very glad to have found your channel -- your videos are beautifully illustrated, concisely and thoroughly explained, and you are an engaging, very likeable teacher. This video leaves me with one big question, however, which is, what are the implications of this explanation in the case of a circuit with no resistors? If we remove the resistor you have drawn in your circuit, we know the voltage in the wire must nonetheless at some point go from High P.E. to Low P.E., just as in the case with the resistor. Surely the wire does have some resistance, and rather than 'no force' being required to move an electron through the wire, the battery is doing work and the particle is reaching 'terminal velocity' (drift velocity) due to 'drag' (resistivity of the wire material)? Please, any clarification you can provide would be hugely appreciated! As an Electrical Engineering student, I feel that getting a very firm conceptual grasp of voltage and current is absolutely paramount for my future success -- your videos so far are a beacon of light! I will be infinitely thankful for any help you can offer in addition to the huge help your videos have already been!
By the way, how does this concept align with 'velocity of electrons across the whole circuit remains the same'? I mean when electrons are losing their potential energy in the resistor, they should loss their velocity, right? Or are there other ways to loss energy without losing the velocity in the resistor?
Their kinetic energy stays the same! Think of a ball falling down! It's potential energy gets converted to kinetic energy increasing it's speed. Now, consider a feather falling down! It's kinetic energy stays the same as the potential energy is converted into heat!
@@Mahesh_Shenoyor like a spherical ball in a viscous liquid at terminal velocity,, it's the same right the viscous force is analogous to air resistance ?
Brother i saw your video on why current is same in series circuit and I saw many other videos on this topic but no one explained this topic as well as you did i realy like it and appreciate your work please make a video on why voltage is same and current is different in parallel circuit ?
I need this video if there isn't one yet 😭😭 Like- WHYY Voltage is the SAME in parallel circuit I just asked my lecturer about this and he keeps showing me the calculations to prove it but i need the explanation not just the calculations 😢😢
Hm, so essentially, an electron gains some Joules of energy because of the chemical interactions in the battery. This is akin to a child gaining G.P.E. after his father raises him back up to the start of the slide. Then, there is no electric force in the wire and all electric force is concentrated on the resistor. Why? Well, that's a separate video. But, we can still compare this to our analogy. The wire where there is high P.E., we can compare that to the starting area of the slide having a wide area. No matter where it is in the starting area, the child remains to have high P.E. because it is still the same height. Similar logic in the wires. Now, when the electron goes to the resistor, that's when the energy is all lost. This is similar to when the child finally slide down the slide and therefore lose his high P.E. Then, the wire from after the resistor up to the opposite terminal of the battery all has same low P.E., which is akin to the ground. Because of this, we can say that the voltage across the battery is the same across the resistor. *Voltage is the amount of energy (Joules) per Coulumb of charge.
Since current can be different in parallel but voltage is same then why voltmeter is made up of very high resistance I think it becouse we assume if voltmeter have low Resistance current will pass through them but voltage is same
Love this video style of you appearing in the corner of a KA-style explainer! Also why isn't this video on KA?! It's questions like these that I hope KAI covers in the in-progress science courses! :)
@@Mahesh_Shenoy Yay! For backing your claims, do mention that using non-KA videos on KA has precedent: World History Project uses Crash course videos, and US Science biodiversity videos are by a non-KA research group. In fact, for Class 9 sciences you can use Aanand's videos from his StayQrious channel. (He made those for his school's self-paced course, but the videos are free for all-and have the KA conversational tone!)
I also have another question. If we remove the resistor and create a short circuit, it will mean there will be no voltage drop since we are assuming we are using a super conductor. How will it then obey the law that the voltage drop must equal the voltage supplied
Damn thanks for the video, it cleared out my almost my all doubts but what if there's no resistor in the circuit? Assuming there's no resistor in the circuit means the energy gained by electrons wouldn't be spent anywhere (cause there's no resistor) so if that's the case then the energy would be same everywhere. So, when electrons comes to positive terminal, it'd have same amount of energy, which contradicts to the example where all the energy is lost when object approaches A from B. Also, what would battery do to that electron which already has an electron? would the electron gain even more energy and continue to gain energy at each interval?
Great explanation. I have measured the voltage referring to conventional flow. Just before the resistance is battery voltage. The resistance uses almost all of the voltage except what is required to overcome rest of the resistance in the circuit to make it back to the battery. Or am I just looking at it differently?
New comment to an old video, which I really enjoyed. In all fairness to Ben Franklin, lightning appears to come from the heavens and go to the earth, even though the electrons are moving in the opposite direction. So not so unreasonable that he got it wrong. Unfortunately, the rest of us engineers have been stuck with that for 250 years.
No change in PE at the wire means if I use multimeter across the two points of wire, it means no voltage? Sorry I am not good in this. I am just learning.
Thank you for sharing your lessons on UA-cam. I also like Walter Lewin. After studying electricity for so many years, we learned all kinds of calculations, but I don't even know how electricity works. Thank you for making me understand. I have a question, according to U=El, the voltage of the resistor is larger than that of the wire, microscopically because the electron needs to go faster, which means more force to go through the resistor, is it? According to i=QnAv, in the past I thought that E would cause more electrons to drift, so the microcosmic effect of the voltage of the resistor is that more electrons move faster. Later I discovered that only the electrons moved faster, and the number of electrons involved in the movement did not change, that is, n did not change, only v changed. Yeah?
When you say that there is no force in a wire, is not there the electric field throughout the wire due to the battery, which in turn would propose a force? and when the electron leaves the resistor with no energy at all, how does it flow to the positive terminal without any force and electric field?
I disagree about flow direction. Negative battery post or house current sucks amperage. Generators are grounded to push/pump negative charges from Earth or grounding body, in which is left a positive imbalance. Stronger negative charges merely require weaker negative charge for function as positive for completing a circuit, as they are restored into balance. Wiring does carry current around its surface and a weaker electric field. Ohms occur when insides of wire is energized by heat expanded protons, which increases amperage drain. As the generator is a pumping portal, the appliance determines drains upon current. Thicker wire allows more current availability, but does not impose it. Thus a heating element requires thicker wiring to pull current through the ohms’ drain from the grounding. Wow I just got an advanced intuition!!
It was an awesome explanation, But I have a doubt that , If the energy given by the battery to 1C charge used up when it is out of resistor , then to continue it's path, from where is it going to again retain the energy which was previously given by battery? .
It's because in the absence of transient magnetic fields, electric fields are conservative vector fields. This means, that if a charge follows an electric field around a closed loop path, the net work done on it by the electric field will be zero. There will be no paths that repetitively do work, or take energy from it, as it repeats the paths. The current attempts different flow rates through each path, but if an amount that is inconsistent with Ohm's and Kirchhoff's law flows, a feedback loop will correct it to settle toward an steady state behavior where the voltage drop across both paths is equal. Since the feedback happens so quickly, the amount of time it takes to correct itself will be imperceivably small.
What if two or more resistors are used u said at one end of resistor there is high p but at another there is low p approx 0 you said so in resistor two how can 0 p be transferred
Sir I am in 9th class ICSE.The definition Of PD is the Work done by the electric force from the terminals to move a charge from one point to another.But if I increase the length of the wire making the electrons to move a longer distance to reach the bulb the bulb should glow more brightly as I am increasing the displacement component.But why does not that happen?
@@Mahesh_Shenoy but sir I am unable to find ur charging and discharging videos for capacitor in which includes equation for how much accumulated (charging) or lef(discharging)
Surely as the kid is being lifted, the kid is sapping the energy from the gravitational field and stores it as potential energy. The field saps the energy from the kid as he slides down the slide?
12:38 how can you say there is no change in P.E as the electron is in motion(potential energy should convert into K.E) so total energy content i.e. the mechanical energy should remain same.Therefore according to me at negative terminal it is having the highest P.E and at positive it has the highest Kinetic energy(in ideal case no resistance of the wire or any external resistor).Is it so?
While we wait for Mahesh's answer here's mine: learn with Mahesh's videos on Khan Academy and FloatHeadPhysics! And get free wisdom from his Linkedin posts! It's remarkable he posts EVERY DAY 9am IST! I hope all those essays are published in book form someday.)
Not sure if I have a good answer for this. But, I would advocate for 'invoking curiosity' & 'encouraging mastery.' Invoke curiosity by always connecting (rigorously, not just at a surface level) connecting things with complex, perplexing phenomena! It's easiest to do that with physics, really! Encourage mastery by attempting to answer things from the first principles! Students often say, 'I understand, but I can't explain it.' My reply is, 'if you can't explain it in simple words, you haven't understood it!' I would love for other folks to share their perspective. This is such a great and challenging question to answer!
@@Mahesh_Shenoy ya Super correct By the way I am a fellow of 9th grade So can you explain accelerated motion and multiple questions related to acceleration and retardation.... ?
I assume 'gravity' is your favorite concept to make other things easier. From your Khan Academy video, I've seen you numerous time to use gravity to make other concepts crystal clear.😃
Yes yes! One of the most powerful way of learning physics is to connect something you don't have intuition for to something analogous that you do have an intuition for.
Sir I am in 9th class ICSE.The definition Of PD is the Work done by the electric force from the terminals to move a charge from one point to another.But if I increase the length of the wire making the electrons to move a longer distance to reach the bulb the bulb should glow more brightly as I am increasing the displacement component.But why does not that happen? Please reply Sir
what if this circuit is connected with a load let say bulb you said it loses all potential when passing through resistance wire then how will it provide energy to the bulb and make it light
Hi, I have learned a lot from your videos. But this explanation seems to be wrong: 1. You say the electric field is conservative. Correct. However, it is not the same electron that is travelling from the negative terminal to the positive terminal. So, your path-integral explanation is incomplete. 2. Also, when an electron aggregates at the positive terminal, it is NOT pumped back by the battery. It is instead just "absorbed" by the electrolyte in the battery. So no work is done by the battery per se to "move" electron from the positive to negative terminal. After going through several videos/articles in books and the internet, however, this concept is still not well explained, and I still struggle to truly understand what is truly going on. So, could you please redo this video with more depth? Thank you. Grateful. For everything!
at 4:50, u mentioned that electrons don't need a force to move through the wire (resistanceless wire). But, when electrons take a turn in the wire, there is a change in the velocity of the electron, which requires a force to do so. How do u explain that classically?
Yes sir, exactly. That's what I am confused about. It they get a bump, where from do they get the bump? And during that process, will they not lose a part of their potential energy?
mastery learning via youtube vids vs fixed pace learning which is followed in institutions....What's better? If mastery learning is better...how exactly do we make it practical...will this work: You start by setting time slots for learning a chapter (from UA-cam/byjus/Khan academy educational videos) every day...but u don't set a deadline...you move on to the next chapter once you've completed the material properly without the learning gaps No targets and other planning...
Yea, but practically you can't learn completely in one go. Nor are there perfect ways of guaranteeing it. An efficient way would be to go forward with some level of proficiency (like the traditional schools but with a much higher bar for 'passing'), but then come back for mastery (unlike the traditional schools in which your previous scores are set in stone)
Charges in general do, not necessarily solo electrons specifically. Inside a discharging battery, it could be positive ions flowing from negative to positive, or it could be negative ions flowing from positive to negative, or a superposition of both simultaneously. The details depend on the specific battery chemistry. Since a battery is not a capacitor, charges aren't building up at the terminal, they are regrouping in the electrochemistry, as chemical energy converts to electrical energy, moving ions across the two terminals inside it. This is why Franklin did us a favor, when setting the "wrong" sign convention of charge. He unintentionally forced us to be more flexible with our definition of current, so we are more willing to think of it as charges in general, rather than electrons specifically.
Negative charge close to another negative charge (like the negative terminal of a battery) wants to go away from it, right? So, if we let it go, what happens to the kinetic energy? And can you think about where did that kinetic energy go or come from? And finally, can you use that to think about the potential energy when charges are close vs when they are farther away?
If you have an impossibly perfect voltage source with no internal resistance, you would accelerate the electrons indefinitely, and their potential energy would convert to kinetic energy. You still will have some inductance, even for a circuit made from superconducting wires, since a single loop has a little inductance. That inductance will be the only impedance of the circuit. This means the equation of motion of the circuit will be: L*di/dt = V Isolate di/dt: di/dt = V/L Integrate both sides: i(t) = V/L * t + i0 This means, starting with no initial current, the current will linearly grow in proportion with the operating time. The ramp rate of the current will be V/L.
You state that there are no forces acting on the electrons in the wire, but there is a force in the resistor. That seems to contradict the idea that electric forces acting on a circuit are determined by the electric field established mainly by the battery. How can the forces change that much depending on which point you are located on the circuit? I thought that the battery's electric field was pretty much independent of the resistor and wire?
@@Mahesh_Shenoy So a resistor is necessary in order to have electric force? You are saying that since there is no resistance in the wire, that means that the electric field from the battery is producing no force on the electrons in a steady current? That doesn't make sense to me. Does gravity not exist if there is no resistance? Are there no electromagnetic forces in space if there is no resistance? The latest video did not clear my confusion.
I love how you are thinking. This is exactly how you should think - "what breaks if xxx happens?" So, let's say the voltage goes to zero after the first resistor. Then, there will be no voltage across the second resistor. Meaning there will be zero current across the second resistor. But there will be a current across the first one. We could say that 'can't' happen, but let's imagine if that happened. What happens next? What do you think?
🤣🤣I just questions you at the moment when you say that it will be at high potential and the other should be at low potential but now my doubt is clear thx
Work is negative in the definition of potential energy, so that work done by a force field, means potential energy decreases, and work done by an external agent (or existing kinetic energy) against a force field, means potential increases. Change in potential energy is the negative of the work done by the force field. Instead, it equals the work done by an external agent working against the force field, or equals the work the force field can do, when the force is allowed to act.
For your second question, consider what would happen if the parent and kid were astronauts, doing a spacewalk. The parent (plus spacesuit) is 200 kg, and the kid (plus spacesuit) is 50 kg. For the thought experiment, let Cavendish's big G be 1 N-m^2/kg^2, albeit extremely unrealistic. The kid and parent start out 1 meter apart, and move to 5 meters apart. Suppose they have of long pole of negligible mass between them, that they can crawl along, so they can use both compression and tension between them for their movements. At 1 meter apart, their GPE will equal -50*200/1 = -10 kJ At 5 meters apart, their GPE will equal -50/200/5 = -2 kJ Collectively, the parent-child system, gains 8 kJ of GPE. But who's body is storing it? Consider what happens, from the center of mass reference frame. At state 1, the center of mass is 20 cm from the parent, and 80 cm from the child. At state 2, the center of mass is 1 meter from the parent, and 4 meters from the child. From state 1 to state 2, the parent moved 80 cm, relative to the center of mass. Meanwhile, the child moved 4.2 meters during this same event, relative to the center of mass. Since work is an integral of force relative to displacement, and they both have to apply the same force to the pole at every point along the way per N's 3rd law, this means the child gains 5.25 times as much GPE as the parent. This means the child stores 6.72 kJ of addt'l GPE and the parent stores 1.28 kJ of addt'l GPE. Long story short, the SMALLER object is the one storing the potential energy, because the smaller object has a lot more displacement. Switch to the Earth and the child instead, and the Earth's motion is not even the size of a molecule, as the child is carried up a 10 meter staircase. So the child is storing the vast majority of the gain in GPE, instead of the Earth.
I'm bothered by how much you are emphasizing how there are no changes anywhere but the battery and the resistor. I get that you mentioned that in the real world the wire would have to be a super conductor for that to be true, but you said that once and then treat the wire as ideal, potentially giving people the impression that wire has no resistance and only 'resistors' in a circuit will cause voltage to drop.
Classical answer - there is a force, to begin with, that sets them up in motion, but then the force disappears! But remember, electrons are NOT tiny balls of matter. They don't really obey classical mechanics. Yet, you can still predict a lot with it!
But the electron needs energy to move through the rest of the wire(after the resistor), so if it has lost all its potential energy - it means the electron has no energy. But its moving, so it must have kinetic energy. WHERE is that energy coming from?
When your favorite teacher teaches you in his own channel! When I found you on Khan Academy, I searched for your UA-cam channel. Though there were videos, you weren’t regular. Great to see you uploading lectures regularly. Take love from Bangladesh. ❤️
Wow, thanks Isteak! Yes, trying to be more regular here now!
@@Mahesh_Shenoy sir why potential difference (voltage ) is same in parallel? Sir please reply .
@@harshad1526 In a conducting material (like a wire), voltage is the same everywhere. So if you have any number of points on a wire connected with nothing in between, they are at the same voltage. Now, imagine three resistors of different resistances connected in parallel. The left side of the resistors are all connected with a wire, so their voltage will be the same, call it V1. Now, their right sides are connected by a wire as well, so their voltages will be the same, call it V2. So, each resistor will have a voltage drop of V2-V1 volts.
This applies to any component whether it be batteries, capacitors, inductors, whatever, since voltage is the same throughout any conducting material. (Assume zero resistance)
I can't describe how much you helped me!!!
I am a 10th grader and i had the same exact doubt which is in the video and i couldn't get it solved because of which I wasn't able to continue the chapter. I researched everywhere but my doubt was not fully clear. It may seem weird but i literally cried because i couldn't understand anything and find meaning to things and after that i gave up and thought I'll have to accept things to complete my syllabus but as i continued the chapter, I encountered another confusion, which was why does current remain same after passing through a resistor. I searched, watched many videos, didn't understand anything, watched yours, fully understood and then watched this one. You won't believe me you came like a god. I could score full marks by just understanding what's given in the book but i don't study for marks and my brain can't rest if I have a doubt. I have never commented this long on any video
Thank you sooo much sir!!!
I am studing electrotechnics at PW (Poland) and i have to truly admit that's (and other videos) the best explenation (especially How circuts really works) i've ever heard. Despite of many bigbrain profesors (it is not an insult) nobody could explain to me these things as clearly as you did. It is a big, increadbly improtant amount of yours work. And it is not just an another courious video like many other videos "something you didnt know", it has big impact how we see the world even if we're not technician. It is our duty as humanity to keep trying understand and describe what we see accordilngy to its profession.
You are amazing bro . I had asked this same question to my school teacher but no one had answer . They also understand my question that electron should have more energy but no one had courage to think in opposite to books text . You are a true teacher .❤
Thanks, Mohan! I too had the same doubt and always wanted an explanation in terms of electrons and not some hypothetical positive charge!
@@Mahesh_Shenoy legends also had doubt🤔
Hay mohan i know you are an indian due to your name mohan name of lord god
@@scienceacademydhruti8382 ya! you are right .are u Indian??
@@Mohan-cz2cz yes also why i know that you
Remarkable explanation, helped me grasp something I couldn't in the past 10 months. You are an exceptional teacher!
Man, I discovered your channel a few weeks ago and I am addicted to your videos. I have already seen dozens of them. I love how you explain everything in order to understand and not to memorize.
You are the best man, greetings from germany
Wow, thanks. Super glad to hear this :)
Yes would like to know about the temporary state and thanks for the video you are making physics much more intresting.
Thanks for the suggestion!
Ok...thanks for these last two videos. Really explanatory. Just one question though. If voltage determines how much current flows through a circuit and how fast, can we say that the voltage drop is experienced across the entire circuit though affected by the resistor alone. The reason I'm asking this is because you said in your previous video that the speed of the electron is affected by the resistance and all the electron pay the price for that resistance in their speed. I don't even know if i am making any sense.
Yes we do wants to know the temporary state😇. Is this the transient state when current is yet to go maximum?
Yes, exactly! I initially added it in the video, but the video just blew up! Thanks for the vote!
Wow I just found your channel and I am really amazed by your explanations . These are explanations I always looked for. Thank you so much for your work.
Thanks for the e comment, Manoj :)
Mahesh, I'm very glad to have found your channel -- your videos are beautifully illustrated, concisely and thoroughly explained, and you are an engaging, very likeable teacher.
This video leaves me with one big question, however, which is, what are the implications of this explanation in the case of a circuit with no resistors?
If we remove the resistor you have drawn in your circuit, we know the voltage in the wire must nonetheless at some point go from High P.E. to Low P.E., just as in the case with the resistor.
Surely the wire does have some resistance, and rather than 'no force' being required to move an electron through the wire, the battery is doing work and the particle is reaching 'terminal velocity' (drift velocity) due to 'drag' (resistivity of the wire material)?
Please, any clarification you can provide would be hugely appreciated! As an Electrical Engineering student, I feel that getting a very firm conceptual grasp of voltage and current is absolutely paramount for my future success -- your videos so far are a beacon of light! I will be infinitely thankful for any help you can offer in addition to the huge help your videos have already been!
Simply awesome explanation!
And yaa we do want the temporary state video!
And there are 6.25*10^18 electrons in one Coulomb.
Glad you liked it. Will do!
First video I found on youtube from Indian creator who make such a depth content(except book authors)
Wow, thanks for acknowledging that!!
By the way, how does this concept align with 'velocity of electrons across the whole circuit remains the same'? I mean when electrons are losing their potential energy in the resistor, they should loss their velocity, right? Or are there other ways to loss energy without losing the velocity in the resistor?
Their kinetic energy stays the same! Think of a ball falling down! It's potential energy gets converted to kinetic energy increasing it's speed.
Now, consider a feather falling down! It's kinetic energy stays the same as the potential energy is converted into heat!
@@Mahesh_Shenoyor like a spherical ball in a viscous liquid at terminal velocity,, it's the same right the viscous force is analogous to air resistance ?
Brother i saw your video on why current is same in series circuit and I saw many other videos on this topic but no one explained this topic as well as you did i realy like it and appreciate your work please make a video on why voltage is same and current is different in parallel circuit ?
I need this video if there isn't one yet 😭😭 Like-
WHYY Voltage is the SAME in parallel circuit
I just asked my lecturer about this and he keeps showing me the calculations to prove it but i need the explanation not just the calculations 😢😢
Fantastic video! And yes, I would like to hear more about the initial temporary state!
The answer where I got is only in this Channel thank you so much sir❤
You are most welcome
Thank you for the video sir! It makes much more sense now.
Glad to hear that, Anjali! Thanks for asking the question!
Yes we do want the microscopic and instantaneous moment when switch is closed Mahesh Sir !
The video is up!
thanku Mahesh i was wondering about this while studing electricity chapter from your videos.
At the time 16:55 you said that no force is working on electron inside the wire then how does that moves? 🙏🏻Sir plz reply and love you sir
Things in motion stay in motion :)
Yes, we want the video on the instantaneous moment of closing the switch.
Already uploaded!
I was so confused about voltage
Thanks for clearing it❤
you are the best
Hm, so essentially, an electron gains some Joules of energy because of the chemical interactions in the battery. This is akin to a child gaining G.P.E. after his father raises him back up to the start of the slide.
Then, there is no electric force in the wire and all electric force is concentrated on the resistor. Why? Well, that's a separate video. But, we can still compare this to our analogy. The wire where there is high P.E., we can compare that to the starting area of the slide having a wide area. No matter where it is in the starting area, the child remains to have high P.E. because it is still the same height. Similar logic in the wires.
Now, when the electron goes to the resistor, that's when the energy is all lost. This is similar to when the child finally slide down the slide and therefore lose his high P.E. Then, the wire from after the resistor up to the opposite terminal of the battery all has same low P.E., which is akin to the ground.
Because of this, we can say that the voltage across the battery is the same across the resistor.
*Voltage is the amount of energy (Joules) per Coulumb of charge.
Since current can be different in parallel but voltage is same then why voltmeter is made up of very high resistance I think it becouse we assume if voltmeter have low Resistance current will pass through them but voltage is same
We want seperate video on intermediate state of flow of else electrons for that fraction of a sec. Please do a video on that.
Sir you explained this phenomenon due to the accumulation of charges in the transients phase. Which explanation is to be accepted?
Sir why potential difference accros a parallel circuit is same
Love this video style of you appearing in the corner of a KA-style explainer! Also why isn't this video on KA?! It's questions like these that I hope KAI covers in the in-progress science courses! :)
I too wonder the same! Will have a word with the team!
@@Mahesh_Shenoy Yay! For backing your claims, do mention that using non-KA videos on KA has precedent: World History Project uses Crash course videos, and US Science biodiversity videos are by a non-KA research group. In fact, for Class 9 sciences you can use Aanand's videos from his StayQrious channel. (He made those for his school's self-paced course, but the videos are free for all-and have the KA conversational tone!)
please make a video on why the voltage is equal in parallel connection
I also have another question. If we remove the resistor and create a short circuit, it will mean there will be no voltage drop since we are assuming we are using a super conductor. How will it then obey the law that the voltage drop must equal the voltage supplied
good video. But electrons don't actually go from the positive terminal to the negative terminal in a battery, do they? Isn't that the ions?
Great analogies, great teacher, thank you 👍
Very interesting explanation. Thank you. You made reference to another video as a follow up to this one. Is this a available to watch? Many thanks
Damn thanks for the video, it cleared out my almost my all doubts but what if there's no resistor in the circuit? Assuming there's no resistor in the circuit means the energy gained by electrons wouldn't be spent anywhere (cause there's no resistor) so if that's the case then the energy would be same everywhere. So, when electrons comes to positive terminal, it'd have same amount of energy, which contradicts to the example where all the energy is lost when object approaches A from B. Also, what would battery do to that electron which already has an electron? would the electron gain even more energy and continue to gain energy at each interval?
But then too your vedio solved most of my concept
Glad to hear that!
Great explanation. I have measured the voltage referring to conventional flow. Just before the resistance is battery voltage. The resistance uses almost all of the voltage except what is required to overcome rest of the resistance in the circuit to make it back to the battery. Or am I just looking at it differently?
Bod you are the god of physics
New comment to an old video, which I really enjoyed. In all fairness to Ben Franklin, lightning appears to come from the heavens and go to the earth, even though the electrons are moving in the opposite direction. So not so unreasonable that he got it wrong. Unfortunately, the rest of us engineers have been stuck with that for 250 years.
Super Sir 🎉. Sir could you please do a video on entropy
18:02 how does the circuit know all of this? A doubt I’ve had for ages. Which video should I see for this?
If we change the resistor then it's also losses all energy?
Sir if there will not any resistance in circuit then the potential energy increases after every round it can go to infinity also?
If we zero resistance in the circuit, I think our model breaks down and we need to look at things using quantum mechanics!
I bet you can you explain these same concept with two resistors in series ?
Yes!
Sorry If you feel annoying but can try make a vedio with two resistor?
Sir how in the resistor their is electric force which is making the electron to accelerate
Plz upload this module related to emf
No change in PE at the wire means if I use multimeter across the two points of wire, it means no voltage? Sorry I am not good in this. I am just learning.
Yes. But real wires have some resistance and hence have some voltage drop across them!
Thank you for sharing your lessons on UA-cam. I also like Walter Lewin. After studying electricity for so many years, we learned all kinds of calculations, but I don't even know how electricity works. Thank you for making me understand. I have a question, according to U=El, the voltage of the resistor is larger than that of the wire, microscopically because the electron needs to go faster, which means more force to go through the resistor, is it? According to i=QnAv, in the past I thought that E would cause more electrons to drift, so the microcosmic effect of the voltage of the resistor is that more electrons move faster. Later I discovered that only the electrons moved faster, and the number of electrons involved in the movement did not change, that is, n did not change, only v changed. Yeah?
Yes. Everything is on point. But n is the number density. That only depends on the material (and temperature)
Mahesh bhai mai apka diwana ho chuka hun😂❤
What happens if we use a high voltage battery in a circuit with lower voltage resistors or a low voltage battery with a higher voltage resistor?
Video on inductance please
I got a couple AA batteries in a box. Are chemical reactions happening right now?
When you say that there is no force in a wire, is not there the electric field throughout the wire due to the battery, which in turn would propose a force? and when the electron leaves the resistor with no energy at all, how does it flow to the positive terminal without any force and electric field?
I disagree about flow direction. Negative battery post or house current sucks amperage. Generators are grounded to push/pump negative charges from Earth or grounding body, in which is left a positive imbalance. Stronger negative charges merely require weaker negative charge for function as positive for completing a circuit, as they are restored into balance. Wiring does carry current around its surface and a weaker electric field. Ohms occur when insides of wire is energized by heat expanded protons, which increases amperage drain.
As the generator is a pumping portal, the appliance determines drains upon current. Thicker wire allows more current availability, but does not impose it. Thus a heating element requires thicker wiring to pull current through the ohms’ drain from the grounding. Wow I just got an advanced intuition!!
It was an awesome explanation,
But I have a doubt that ,
If the energy given by the battery to 1C charge used up when it is out of resistor , then to continue it's path, from where is it going to again retain the energy which was previously given by battery? .
It gets used because it doesn't need more energy for the rest of the path! The rest of the path has zero resistance!
I like your explanation and my problem is solved😊😊😊😊 . But I have another problem , why does voltage remain constant in parallel circuit?
It's because in the absence of transient magnetic fields, electric fields are conservative vector fields. This means, that if a charge follows an electric field around a closed loop path, the net work done on it by the electric field will be zero. There will be no paths that repetitively do work, or take energy from it, as it repeats the paths.
The current attempts different flow rates through each path, but if an amount that is inconsistent with Ohm's and Kirchhoff's law flows, a feedback loop will correct it to settle toward an steady state behavior where the voltage drop across both paths is equal. Since the feedback happens so quickly, the amount of time it takes to correct itself will be imperceivably small.
What if two or more resistors are used u said at one end of resistor there is high p but at another there is low p approx 0 you said so in resistor two how can 0 p be transferred
very clear sir!
So the resistor lowers the current in the whole series circuit. And it also uses all the energy from the electrons, thus there is a voltage drop?
Resistor vs wire video pls. What happens for the first few milli seconds
Sir I am in 9th class ICSE.The definition Of PD is the Work done by the electric force from the terminals to move a charge from one point to another.But if I increase the length of the wire making the electrons to move a longer distance to reach the bulb the bulb should glow more brightly as I am increasing the displacement component.But why does not that happen?
Sir can you please please please make video for all concept which lead to working of (capacitor, charging, discharging,equations derived ))
I have made quite a few of them at Khan Academy. Can you check those out?
@@Mahesh_Shenoy link??
@@geetikaacharya2325 www.khanacademy.org/science/in-in-class-12th-physics-india/x51bd77206da864f3:alternating-current
@@Mahesh_Shenoy but sir I am unable to find ur charging and discharging videos for capacitor in which includes equation for how much accumulated (charging) or lef(discharging)
@@geetikaacharya2325 Oh, you are talking about DC circuits! Got it. Will add to my list!
Thank Mahesh sir love from Bangladesh
Surely as the kid is being lifted, the kid is sapping the energy from the gravitational field and stores it as potential energy. The field saps the energy from the kid as he slides down the slide?
why the voltages is equale in an empty wire plss?
12:38 how can you say there is no change in P.E as the electron is in motion(potential energy should convert into K.E) so total energy content i.e. the mechanical energy should remain same.Therefore according to me at negative terminal it is having the highest P.E and at positive it has the highest Kinetic energy(in ideal case no resistance of the wire or any external resistor).Is it so?
The speed of the electrons stay the same throughout! So no change in KE!
Hi Mahesh
Please tell me how to stop fearing from physics?
You know
It's a big hesitation which you can find in any students heart ..
Please
While we wait for Mahesh's answer here's mine: learn with Mahesh's videos on Khan Academy and FloatHeadPhysics! And get free wisdom from his Linkedin posts! It's remarkable he posts EVERY DAY 9am IST! I hope all those essays are published in book form someday.)
Not sure if I have a good answer for this.
But, I would advocate for 'invoking curiosity' & 'encouraging mastery.'
Invoke curiosity by always connecting (rigorously, not just at a surface level) connecting things with complex, perplexing phenomena! It's easiest to do that with physics, really!
Encourage mastery by attempting to answer things from the first principles!
Students often say, 'I understand, but I can't explain it.'
My reply is, 'if you can't explain it in simple words, you haven't understood it!'
I would love for other folks to share their perspective. This is such a great and challenging question to answer!
@@Mahesh_Shenoy ya
Super correct
By the way I am a fellow of 9th grade
So can you explain accelerated motion and multiple questions related to acceleration and retardation.... ?
I assume 'gravity' is your favorite concept to make other things easier. From your Khan Academy video, I've seen you numerous time to use gravity to make other concepts crystal clear.😃
Yes yes!
One of the most powerful way of learning physics is to connect something you don't have intuition for to something analogous that you do have an intuition for.
Sir I am in 9th class ICSE.The definition Of PD is the Work done by the electric force from the terminals to move a charge from one point to another.But if I increase the length of the wire making the electrons to move a longer distance to reach the bulb the bulb should glow more brightly as I am increasing the displacement component.But why does not that happen?
Please reply Sir
WELL DONE👍
what if this circuit is connected with a load let say bulb you said it loses all potential when passing through resistance wire then how will it provide energy to the bulb and make it light
Thank you!!
Hi, I have learned a lot from your videos. But this explanation seems to be wrong:
1. You say the electric field is conservative. Correct. However, it is not the same electron that is travelling from the negative terminal to the positive terminal. So, your path-integral explanation is incomplete.
2. Also, when an electron aggregates at the positive terminal, it is NOT pumped back by the battery. It is instead just "absorbed" by the electrolyte in the battery. So no work is done by the battery per se to "move" electron from the positive to negative terminal.
After going through several videos/articles in books and the internet, however, this concept is still not well explained, and I still struggle to truly understand what is truly going on.
So, could you please redo this video with more depth?
Thank you. Grateful. For everything!
I cant imagin voltage when current flow thought resistor in a paralley with
series circuit in each resistor.
what about in parallel?
But .... Positive terminal has high potential??
Sir u r legend
at 4:50, u mentioned that electrons don't need a force to move through the wire (resistanceless wire). But, when electrons take a turn in the wire, there is a change in the velocity of the electron, which requires a force to do so. How do u explain that classically?
Nice question! It may get a tiny bump from somewhere?
Yes sir, exactly. That's what I am confused about. It they get a bump, where from do they get the bump? And during that process, will they not lose a part of their potential energy?
Can u pls do a video about resistor, resistance and resistivity?plss
mastery learning via youtube vids vs fixed pace learning which is followed in institutions....What's better?
If mastery learning is better...how exactly do we make it practical...will this work:
You start by setting time slots for learning a chapter (from UA-cam/byjus/Khan academy educational videos) every day...but u don't set a deadline...you move on to the next chapter once you've completed the material properly without the learning gaps
No targets and other planning...
Yea, but practically you can't learn completely in one go. Nor are there perfect ways of guaranteeing it.
An efficient way would be to go forward with some level of proficiency (like the traditional schools but with a much higher bar for 'passing'), but then come back for mastery (unlike the traditional schools in which your previous scores are set in stone)
6:06 we want that
I have enough votes, I will do it!
16:16
6 * 10^18 electrons
electrons dont rally pass through the battery right?
they just collect at the positive terminal, and neutralise
Charges in general do, not necessarily solo electrons specifically. Inside a discharging battery, it could be positive ions flowing from negative to positive, or it could be negative ions flowing from positive to negative, or a superposition of both simultaneously. The details depend on the specific battery chemistry. Since a battery is not a capacitor, charges aren't building up at the terminal, they are regrouping in the electrochemistry, as chemical energy converts to electrical energy, moving ions across the two terminals inside it.
This is why Franklin did us a favor, when setting the "wrong" sign convention of charge. He unintentionally forced us to be more flexible with our definition of current, so we are more willing to think of it as charges in general, rather than electrons specifically.
@@carultchoh ok thanks!
Shouldn't current and potential energy be in terms of electrons because they are the ones who move more and all? I hate conventional current flow
Yea, but they are negative charge and we hate negatives!
Sir I can't understand how negative charge has high potential energy please reply sir
Negative charge close to another negative charge (like the negative terminal of a battery) wants to go away from it, right?
So, if we let it go, what happens to the kinetic energy? And can you think about where did that kinetic energy go or come from? And finally, can you use that to think about the potential energy when charges are close vs when they are farther away?
could anyone explain what will happen if there is no resistor, how will the electrons lose the potential energy?
That’s a great question! It’s not possible though!
The battery itself will provide some resistance
If you have an impossibly perfect voltage source with no internal resistance, you would accelerate the electrons indefinitely, and their potential energy would convert to kinetic energy. You still will have some inductance, even for a circuit made from superconducting wires, since a single loop has a little inductance. That inductance will be the only impedance of the circuit.
This means the equation of motion of the circuit will be:
L*di/dt = V
Isolate di/dt:
di/dt = V/L
Integrate both sides:
i(t) = V/L * t + i0
This means, starting with no initial current, the current will linearly grow in proportion with the operating time. The ramp rate of the current will be V/L.
You state that there are no forces acting on the electrons in the wire, but there is a force in the resistor. That seems to contradict the idea that electric forces acting on a circuit are determined by the electric field established mainly by the battery. How can the forces change that much depending on which point you are located on the circuit? I thought that the battery's electric field was pretty much independent of the resistor and wire?
The electric field strength depends on the resistors! Does my latest video clarify why that happens?
@@Mahesh_Shenoy So a resistor is necessary in order to have electric force? You are saying that since there is no resistance in the wire, that means that the electric field from the battery is producing no force on the electrons in a steady current? That doesn't make sense to me. Does gravity not exist if there is no resistance? Are there no electromagnetic forces in space if there is no resistance? The latest video did not clear my confusion.
@@mjciavola There is no electric field in the wires!
@@Mahesh_Shenoy That's news to me. Go to 5:15 minutes into this video: ua-cam.com/video/C7tQJ42nGno/v-deo.html
@@Mahesh_Shenoy That's news to me. Go to 5:15 minutes in this video: ua-cam.com/video/C7tQJ42nGno/v-deo.html
What if there is no resistor and the wire has zero resistance
Now explain the same concept with an Infinite Resistance (Open Circuit - No Electron Flow). How much Voltage between the Resistor Terminals?
After losin potential energy how it travel
Dude how do u even know this things ❤😊
Why doesn't voltage goes to zero after the first resistor?
I love how you are thinking. This is exactly how you should think - "what breaks if xxx happens?"
So, let's say the voltage goes to zero after the first resistor. Then, there will be no voltage across the second resistor. Meaning there will be zero current across the second resistor. But there will be a current across the first one. We could say that 'can't' happen, but let's imagine if that happened. What happens next? What do you think?
Hey hey the negative terminal is at low potential and positive terminal is at high potential
🤣🤣I just questions you at the moment when you say that it will be at high potential and the other should be at low potential but now my doubt is clear thx
Cool
best
Thnaks
so in the case of parent taking the kid up, does KID store the potential energy or does earth? why is work negative?
Work is negative in the definition of potential energy, so that work done by a force field, means potential energy decreases, and work done by an external agent (or existing kinetic energy) against a force field, means potential increases. Change in potential energy is the negative of the work done by the force field. Instead, it equals the work done by an external agent working against the force field, or equals the work the force field can do, when the force is allowed to act.
For your second question, consider what would happen if the parent and kid were astronauts, doing a spacewalk. The parent (plus spacesuit) is 200 kg, and the kid (plus spacesuit) is 50 kg. For the thought experiment, let Cavendish's big G be 1 N-m^2/kg^2, albeit extremely unrealistic. The kid and parent start out 1 meter apart, and move to 5 meters apart. Suppose they have of long pole of negligible mass between them, that they can crawl along, so they can use both compression and tension between them for their movements.
At 1 meter apart, their GPE will equal -50*200/1 = -10 kJ
At 5 meters apart, their GPE will equal -50/200/5 = -2 kJ
Collectively, the parent-child system, gains 8 kJ of GPE. But who's body is storing it?
Consider what happens, from the center of mass reference frame. At state 1, the center of mass is 20 cm from the parent, and 80 cm from the child. At state 2, the center of mass is 1 meter from the parent, and 4 meters from the child. From state 1 to state 2, the parent moved 80 cm, relative to the center of mass. Meanwhile, the child moved 4.2 meters during this same event, relative to the center of mass.
Since work is an integral of force relative to displacement, and they both have to apply the same force to the pole at every point along the way per N's 3rd law, this means the child gains 5.25 times as much GPE as the parent. This means the child stores 6.72 kJ of addt'l GPE and the parent stores 1.28 kJ of addt'l GPE. Long story short, the SMALLER object is the one storing the potential energy, because the smaller object has a lot more displacement.
Switch to the Earth and the child instead, and the Earth's motion is not even the size of a molecule, as the child is carried up a 10 meter staircase. So the child is storing the vast majority of the gain in GPE, instead of the Earth.
I'm bothered by how much you are emphasizing how there are no changes anywhere but the battery and the resistor. I get that you mentioned that in the real world the wire would have to be a super conductor for that to be true, but you said that once and then treat the wire as ideal, potentially giving people the impression that wire has no resistance and only 'resistors' in a circuit will cause voltage to drop.
But if the force in wire is zero ...them how current originates ???
Classical answer - there is a force, to begin with, that sets them up in motion, but then the force disappears!
But remember, electrons are NOT tiny balls of matter. They don't really obey classical mechanics. Yet, you can still predict a lot with it!
@@Mahesh_Shenoy ok sir At tjis stage I should understand force after starting them disappears ??
But the electron needs energy to move through the rest of the wire(after the resistor), so if it has lost all its potential energy - it means the electron has no energy. But its moving, so it must have kinetic energy. WHERE is that energy coming from?
Great question. As you said yourself, it has lost all the potential energy gained from the battery. Not the KE
@@Mahesh_Shenoy Understood! thanks a lot.
16:15 i think 6.25 x 10 ¹⁸
Yes!
Deep dive! Deep dive!
Will do! Will do!