Top
Online Neet Coaching

"Current Electricity: Videos"

00:00:01 [Music] [Music] hello welcome all of you to this course of lecture what I will be doing in the current and the next few lectures is to discuss about current electricity let me first point out that so far you have discussed charges at rest and what we are going to do in this chapter is to look at charges which are in motion and that is what we call as current now before I go to physics of currents let me also tell you that current occurs in nature as well the most common one being lightning which occurs due to electric


00:01:20 discharge during an electric electrical storm see what happens is this that find drops of water go and reach the cloud at fairly high height they essentially become like ice clouds and when different parts of these clouds they collide with each other they usually lead to generation of electric current and such discharge which you call as lightning could occur between electrically charged regions of a cloud or between two clouds or between a cloud and the ground now of course you all know that the power of lightning could


00:02:13 be quite significant because an average bolt of lightning transfers about 15 Coulomb of electric charge now you wish to tell you that a Coulomb ascender Coulomb is a fairly large amount of electric charge because you might recall that the charge of an electron is 1.6 into 10 to the power minus 19 coulombs so therefore when I talk about 1 Coulomb it means 10 to the power 19 times the charge in an electron and if you are talking about a very large Lightning then the amount of charge that is transferred


00:03:00 could be as high as something like 300 to 400 coulombs and a typical potential difference in a lightening could be as high as 200 thousand to five hundred thousand volts and that can can go even up to as high as thirty million volts in addition to this another thing that occurs in nature and with really beautiful consequences is that Sun emits gases and particles which move towards the space at a fairly high speed and part of which also reaches the earth and some of these which reach the atmosphere


00:03:53 particularly at the higher atmosphere they I happens to ionize things and they sort of work in or circulate in the region of atmosphere known as the ionosphere and and this current they create some beautiful sites known in the northern hemisphere as aurora borealis are also called the Northern Lights and very similar things also happened in the southern hemisphere which we call as the southern light or also known as aurora australis any fact I have shown you a image of the aurora borealis in the northern


00:04:42 hemisphere from NASA public website and but they occur in different types of colors now in addition in nature there are certain fish actually six categories of fish prominent among them being eels and catfish which also emit electric charges now remember that our muscle cells have electric potential and but in some phase they sort of evolved into cells which are called electrolyte cells and which can generate potential differences of the order of 800 to 1000 volts or so and a much smaller scale even within a human


00:05:29 body we know that many of our body functions for example the pumping of blood into our hearts they take place by signals which arrive there from the brains and these signals are also electrical in nature and of course they are much smaller we'll be talking about their magnitude where but but basically these examples that I gave you they're examples of situations where the current is not steady so what we are interested are in situations where the current remains steady and this lecture and the


00:06:15 subsequent ones we would be primarily interested in talking about currents which are steady and later on we'll see that steady currents also become sources of magnetic field very loosely speaking electric current is nothing but flow options you this is the formal definition and let's try to make this a little clearer now let let me say that I have an arbitrary surface some area doesn't matter and suppose I have charges let us say positive charges which I will call Q plus and negative charges group there Q


00:07:21 minus and they are passing through this surface now so whatever enters into that surface comes out so therefore so this is the charge in and they are coming out on the other side of that surface so this is my charged out obviously that's also equal to Q plus and this is the Q mess now so the net amount - which is flowing in is Q plus - Q - now supposing these charges were steadily flowing through that surface then the amount of charge that is going to that surface would be proportional to the time T so this is proportional to


00:08:24 time T during which we make our of the vision so in other words the rate at which the charge flows that I will call as or define formally as my current this is equal to Q divided by T now this of course assumes that my flow is steady but supposing it is not now then I would take the formal definition in a slightly different way and I will say that take a small time interval delta-t now during which the amount of charge that is flows through that surface that I talked about is Delta Q then my current I add that instant around which


00:09:27 I have taken that delta T can be defined as limit of delta T going to 0 I take as small as time interval as possible Delta Q divided by delta T you recall from your calculus that this is nothing but my definition of DQ by DT so this is my formal definition of current let's look at what are the units of current so note that current is defined as charge divided by time so therefore obviously the unit that I expect is Coulomb per second actually so this is given a name ampere actually in SI units the ampere is 00:10:34 defined not as Coulomb per second because Coulomb is not a fundamental unit ampere is it is defined in terms of its magnetic effects but that will be we'll be talking about in later parts so ampere is a fundamental unit in you so let's go back to the cases that we talked about for example typical household appliances in India you know that Indian electricity supply is in the range of 220 to 240 volts and typical current values for household appliances is of the order of a few amperes so let's say up the order of five 00:11:41 amperes or so if you want to compare this with for instance the strength of the current that takes place in and lightning this could be typically several thousand nuggets you or other formulas that I talked about could also go to millions of our beers now on the other side I talked about certain fish like catfish and eel which give out electric currents there again the natural things they are typically about N and a deer on the lower end the human nervous system gives its mouth micro amperes you 00:13:01 so now that we have talked about the definition of electric current let me now try to tell you how exactly we look at the flow of currents though it is not a an exact similarity but there is a lot of similarity with water flow throw of water for instance through a pipe now remember that for example at your homes you have a water faucet and typically there is a pipe which is going through and supposing at this end there is a water faucet and I know that if you open the tap the water immediately starts coming out now what happens is 00:14:04 this we have also observed that there is no time difference between almost no time difference between the time when you per open the tap and the water comes out now actually what is happening is this that water is being pushed from one end but because there is a closed faucet on the other end it is not able to go and it stopped and and so there is no movement of water physically from here to there because their pipe is already full of water now when you open the faucet then basically all that happens is the water gets 00:14:47 pushed but almost as soon as you open it because there is already water at this end the water starts flowing in there so the incoming water is pushing the water which is there in this and of course then the water comes out now almost very similar thing happens in electricity for example at your home now you switch on for example a light and you'll find that there is no perceptible time difference between the time you switch on the light and the light coming up and the main reason is again the same 00:15:30 thing they in the wire which is there there are extra charges already there so what you did when you push the switch is to essentially please provide that push like what I showed here so therefore the what we need to do because the electrons are already there as a part of the matter and what we need to do is to essentially push it so what we will be talking about is how this mechanism of pushing the electrons is arrived at and you know how does charges actually flow so let us look at how is current created 00:16:30 so first thing that you have to recognize is that the ability of a material to conduct electricity depends on the property of the material we know that there are two types of charges there are positive charges and negative charges now what we require is a separation of charges in order to ensure there is a flow of charge now for instance we could create a static charge by rubbing together two materials this you have learnt in your first lecture on electricity where we talked about static electricity for instance if you rub a 00:17:24 piece of amber with animal fur then of course I generate static electricity and then if we touch amber to the ground the current immediately assess through and the static list is lost of course this current that we'll talked about doesn't last for very long and like the other cases that I mentioned these are also not currents which can be utilized in any useful way so so this is known the way one talks about generating electric current so let us now come to what type of materials are suitable for 00:18:23 generating electric current the first thing that we know is all material consists of atoms and molecules and so behavior of a material electrical property or any other property for that matter depends upon the atoms and molecules which constitute a matter and we're interaction ability to conduct also depends upon physical condition of the material for example pressure temperature etcetera we will be talking about one or two of these things later but but this is this is roughly what happens but for the 00:19:27 purpose of electric current the class of materials that we are interested in are known as conductors these are typically substances such as silver copper aluminum etcetera mostly in some state but of course you also have mercury which at normal temperature is a liquid and is an exception so these are materials which are readily conduct electricity you now that of course happens if these things are brought into a closed circuit and an electric field is applied so the reason it happens is that the 00:20:34 atoms in a conductor they have the ability to very easily give up when I say very easily it means with where it will cost a little cost of energy give up one or more valence electrons and and then this valence electrons which are contributed by the atoms which comprise that solid now they all belong to the material as a whole and not to that particular atom or atoms to which it belonged and very frequently we use the world electron gas so these are all so-called free electron gas they're free in the sense that they are 00:21:34 not tightly bound to an atom but they belong to the solid as a whole so belong to solid as a whole now this electron gas that we have talked about when you apply an external electric field they are free to move because as we know charges accelerate in an electric field now in our lectures on electrostatics we have learned that inside conductors I cannot have an electric field so electrostatics you know inside is you what we will see now is that under dynamic condition this statement will not remain valid so let me I will come 00:22:46 back to it again but we will say not to under dynamic condition now we have been just talking about current in mostly solids and in this case since that is the most common form of electrical conduction we have been talking about motion of electrons but let me tell you that conduction or transport of charges do not necessarily happen only with electrons it can happen even with positive charges and the typical example is what is known as an electrolyte you might recall your elementary chemistry a little bit for example if I 00:23:57 have an electrolytic solution let us just take a simple situation like a common salt solution now I know that these are typical common salt these are what are known as ionic compounds the way to happened is this better these sodium atoms and chlorine atoms have this property that be outside the valence electron in sodium item for example was extremely loose in the sense nature was very weakly bound to sodium atom and as a result sodium pudding we easily lose that and when sodium lost an electron this is one example which you 00:24:50 might have seen there so basically what happens is that if it actually loses initial electron and thereby becoming a sodium plus so I should probably write it as this minus electrons so sodium plus plus an electron but this electron that is there is easily attracted by chlorine so chlorine very readily agrees to accept this electron in its valence M and so the chlorine accepts the electron and becomes a negatively charged chlorine ion so therefore what happens in the sodium chloride solution is that we have 00:25:39 instead of sodium chloride together as atoms we have na plus cell lines now so suppose I had a situation like this this is electrolytic solution so for my typical example I am talking about sodium chloride so let us look at that now I insert two electrodes and I will see that I will need to sort of connect them with a battery the positive end connected to one of the electrodes the negative end is connected to the other electrode so this in our usual language this is a positive electrode also called 00:26:25 an anode this is a negative electrode called a cathode now look at this since the cathode is negative the electrode is negative it has the ability of at writing the sodium plus ions so the sodium plus ions will start moving in this direction now likewise the chlorine ions would move in the reverse direction and of course if there is a current this would in there is a closed circuit this would give rise to a current but basically the reason I talk to you was that though generally we talk about electrons being 00:27:17 the agent of conducting electricity we also have the sodium and the chlorine ion for example the positive ions can also conduct electricity and why in fact we will see later on in our lectures on semiconductors that even the absence of electrons there is a vacancies which behave like positive charges they contribute to the electrical current so now what what is the situation in an insulator in an insulator unlike the case of a conductor or the case of an electrolyte for instance the electrons are tightly bound and another result 00:28:02 they are not free to move so tightly bound electrons unlike in the case of a conductor where we have said that there cannot be under static condition electric field inside a conductor in case of insulators different distribution of charges are and the inside the electric field need not be zero at this moment I postpone my definition or the properties of what are called semiconductors because that requires a detailed discussion by itself but we will come back occasionally to this so let us look at first the metals or the 00:29:07 conductors metals are of course conductors and let us look at what happened in electrostatics now suppose I had a piece of metal and I let's suppose that this is a sample and these are my two ends and let us suppose artificially I provided a positive charge plate here and a negative charge here now look at what actually happens the free electrons which are here they would start moving towards thee play to the positive charge and and you see initially before this happens because one end has a positively charged 00:30:08 plate the other end has a negatively charged plate I had essentially created an electric field but in this is a good conductor as soon as this happens this will attract the the positive plate will attract the electrons and of course the as a result the negatively charged nature of the other plate will disappear and the motion of the electrons inside would soon stop soon stop so this is what would happen in static condition but let's look at it slightly differently suppose I had a situation like this but 00:30:49 I did not have a static condition because I had applied an external electric field so let us let us draw the external electric field and see what happens so I have the same situation there and let's suppose I have an external electric field in which this has been placed now I realize immediately electrons would start moving opposite to the direction of the electric field so that will charge up this side and so that would make backside positive the result of this is to create an effective field 00:31:47 inside the material so let us call it in and this will go on till the field inside which was external to begin with that has been exactly canceled and there is no longer any field around there now this is this is precisely what happens and and as a result the picture that emerges out of this is like this a conductor in a an external electric field the field lines are like this no field inside so I have negative charges here the positive charges there this is my external so basically what is happening is this 00:32:46 that it is the electrons which are moving from the right to the left creating an effective electric field and that exactly cancels the external field that we had put the material in and then let filled inside in a static condition is equal to zero now suppose I do something more what I do is I have a method of removing these electrons which come here happiness so basically what I am creating is a pump so let me go back to the same picture again but create dynamic condition so the same picture I had alerted field 00:33:39 and we have seen that this electric field had made this side negative this side positive and what I do is this I have a mechanism we discuss more about what mechanism it is later but supposing there is a method of taking out these electrons and feeding it back there so creating something like a charge pump if you like how we do it I'm not given in this picture but you might have realized that what we do is to join it by a battery and things like that but with this charge pump remove the electrons almost 00:34:35 as soon as they arrive here and then fix it there so this has the effect that no electric field internal electric field will be created internal equal to zero for conduct hood you mean that current could slow regularly and this is the way charges would flow so this is the way the current appears so hence charges in flow so now that we have talked about that current is basically a flow of charge and we have seen that though there are situations where both positive and negative charges could flow most of the 00:35:50 time we are restricted to talking about electrons so let me talk about what about the direction because we all know that for example when I gave the example of water flowing we also know that light has a direction because it depends upon the way they are being pushed so direction of correct now conventionally in spite of the fact that the electrons contribute from the bulk for the bulk of the currents in situations that we are interested in but it has always been defined as the direction of flow of positive charge 00:36:51 so the picture that I gave you a little while back so I have this situation so we said that there are these electrons which are moving to this plate so let me still show that electrons moving in they are being removed continuously so the electron is moving in this direction so according to this definition that I gave you this is a situation where the direction of current is the reverse direction so let me say that that is the direction in which the current is flowing in other words the direction of current 00:37:44 is defined according to a convention as the direction or posit to the direction in which the negative charges flow that is the direction in which the positive charges flow now that is one thing that you would immediately notice that we have said current has a direction however current though it has a direction is not a vector this is something which needs a little a little bit of thinking to appreciate so current i has a direction but is a scaler it is not a vector and this is primarily because it doesn't satisfy the algebraic 00:38:37 law of addition of vectors we will see how currents are added up and in fact we'll be discussing it at a later stage so let us look at I'll go back to our original definition we said DQ by DT in my current so if I take any arbitrary surface so the amount of charge that is flowing through any arbitrary surface is related to current by this relationship integral IDT so we have made a statement that current is not a vector and we have talked about its unit so we define a quantity which is related 00:39:35 to current but turns out to a vector so the current density J is a vector though no current is not affected so let me explain how it works let us suppose I am talking about a current which is passing through an arbitrary sir let me show you a surface here this next suppose is the end of a wire cross section of a wire and the current is entering like this and in living from the surface like any other definition of density I define the magnitude of the current density as the amount of current passing through a unit 00:40:43 8 so let's first talk about the magnitude and then I will come to what is its direction so magnitude of J is I divided by area so this is of course the scalar because current is a scalar area as we understand is the scalar since J is a vector we need to define its direction now you are all aware that if you take an infinitesimal surface area that area can be made as flat as you want by making the surface area smaller and smaller and so that I can associate a direction with this you have learnt even 00:41:46 in your mechanics course for instance so what we are now saying is this that we define D as the direction of the area element in a direction which is perpendicular to the cross-section obviously this definition makes sense only if the area is infinitesimally small now sorry this direction now you realize that every surface has two directions one in which the current is coming in and the other side of the surface is the direction from where the coming current is coming out now we take the direction of the s as that surface 00:42:56 the direction of that surface from which the current is coming out so and we define J to be in the direction of current flow you so what does it mean somebody I have a wire with this cross-section and I have current entering like this so the positive charges are flowing in this direction so that is my direction of J and when the current comes out it is this surface from where we come out and so therefore it is outward normal to this surface so this is your direction of use this implies that J dot DS is 00:43:56 positive for positive correct so current is not a vector but current density which is the point definition by point definition I mean that I take a small enough area I can make that area as small as I like so that density is defined as a point function so at every point in the material I define that is so we have seen that under electrostatic condition there is no field inside a conductor now what happens in such a situation so the electrons are still free and so let us write it down static condition 00:45:00 so no field inside the material so what happens is this that in such a situation the free electrons themselves have water normal thermal velocity now typical thermal velocity of electrons in a metal is on the order of 10 to the power 6 meter per second fairly large velocity now what happens inside the metal is this that these electrons move inside the metal in a random fashion and let me explain to you what actually happens so in a metal there are these ions or atoms which are located there is a periodicity type of 00:46:01 thing but let us not worry about that and going essentially a pattern here so what happens is this if you take a particular electron this electron is continuously colliding with atoms or ions and then a bouncing back back from the atom and then collides with another one so typically a situation could be like this if this is an electron it could go here then here then here so all sorts of things can happen there is no particular pattern and let me explain why this collision is essentially elastic in nature so these 00:46:53 are elastic collision so we are talking about in the absence of any field inside so let us say e inside is zero so elastic collision stiffness now this is something which is very similar to when for instance a very light particle collides against a heavy arrow so for instance a tennis ball bouncing against a wall or a stone bouncing against a truck so we know that a light particle colliding against a heavier mass bounces back almost with an unchanged speed now and only that the direction in which emerge will sort of depend upon 00:47:54 what is the direction in which the collision colliding particles approached the I am and then of course it comes out and the result of collision Andry collision is such that the electron moves around in all directions now if you look at a collection of electrons the because of this random nature the velocities of the electrons different electrons are uncorrelated now so let me write it down the velocities of different electrons are uncorrelated now as a result supposing I say that V I let me put an average sign here 00:49:02 represents the velocity of the is electron the average velocity of V electron if I sum it over I equal to let's say 1 2 let's say n number of particles are there so 1 over m this is equal to 0 there is equal to 0 because the directions of the velocities are hopefully uncorrelated so average velocity of the collection of electrons is zero so let us return to dynamic condition now we have seen that under dynamic condition the electric field inside need not be zero so let's say the inside is 00:50:09 not equal to say now in such a situation the electrons which we said move with a thermal velocity because of the presence of the electric field inside are also accelerated so let's say the electrons are accelerated the velocity or speed with which the moving is still the thermal velocity but they are accelerated what is the result the result is that the picture that I gave you for the static condition roughly holds but because of the presence of the electric field on an average the collection of 00:51:06 electrons would move or drift in a direction opposite to that of the electric field so the collection of electrons or move in a direction opposite to that of the electric field you a simple analogy might help understand this situation supposing you are in a room and there are chairs it's a classroom and a few of you you your eyes are tied and you decide to move around the room now since you cannot see you are likely to bump against the chairs you are also of course likely to bump against yourselves but I assume that for 00:52:15 reasons that I will explain I will assume that you do not collide with each other but collide with the static chips now once you have collided with chair you obviously change your direction and start moving in another direction and again collide with another chair now if this situation where we what happened in case of static condition then after some time if you look at the positions of all the players in the room they would be essentially random which corresponds to the situation the average velocity is 00:52:52 equal to 0 now let me now assume that there is a door to that room where there is a sound signal that is coming up maybe somebody a friend of yours is playing flute there now then since you still cannot see you will be colliding but when after collision you want to change the direction of your motion you are more likely to move towards the direction from where the music is coming so what happens in such a situation after some time that big distribution is still roughly random but on an average the group of students who are there in 00:53:37 that room they will drift towards the door and this is essentially the concept of difference now when I told you that let us assume that you don't collide with each other the analogy is because of this in this case my colliding particles are electrons and the electrons as you know can be regarded as point particle when I compare their dimensions with data bios now since the electrons have negligible volume so the probability that they collide against each other is almost non-existent and because of that 00:54:18 we assume that the electron interaction is neglected now so what happens to the expression for drift velocity in our situation somewhat have returned back to this picture and I assume that I am considering a parallel pipe with a cross-sectional area a and length L now what we are saying is this all the electrons which are within a volume a times L so all electrons within a volume eight times eight we'll pass through the right the face why in this picture this is the direction of the electric field 00:55:42 which is also the direction of the current density and the electrons are on an average moving toward this right and that is the direction of the drift velocity which we represent by VD suppose M is my electron density then the number of electrons which are in that volume is obviously n into L into a so this area is a and the charge that is content is e times n into L into a well this being electronic charge the charge would be negative but in this case I am talking about the magnitude of the charge so in this case my e is the 00:56:41 magnitude of electronic charge Hadj is of course equal to 1.6 into 10 to power minus 19 coulomb so therefore the current density it is given by Q divided by a times T this is the amount that has asked through this surface in time T so therefore this is given by e times n a has canceled out I am left with L divided by T so that is my e times n times the magnitude of ready now sense the direction is opposite to that of the current density I write my current density J is equal to minus e times n times VD 00:57:51 the direction of the current density is opposite to the direction in which the electrons are moving so what I have basically done today is to define what is electric current realize that electric current is simply an alternative name for electric charges which are moving flowing we pointed out that it is not a vector we defined a related quantity called current density and we realized that current density because it's a point function can be regarded a director and we started talking about the concept of 00:58:35 a drift velocity which we will elaborate in more details next time [Music] [Music] you [Music]

Neet Bharath Tutorials
Exams: NEET / IIT-JEE
Audience:
  • Educators of H. School / Intro Undergrad
  • Student
  • Educators of Adv. Undergrad / Grad
  • Researcher
  • Educators
Teachers: Masters Degree / Phd Holders
More Videos For Current Electricity
Register Now!

VIDEO LECTURES FOR CURRENT ELECTRICITY (CLASS 12)

NEET PHYSICS VIDEOS

10 Videos On Current Electricity

Video Lecture 01

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Electric Current and Current Density) | Video #1 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Video Lecture 02

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Drift Velocity and Resistance) | Video #2 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Video Lecture 03

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Mobility and Temperature Dependence of Resistivity) | Video #3 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 04

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Electromotive Force and Ohm's Law) | Video #4 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 05

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Electrical Energy and Power) | Video #5 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 06

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Series and Parallel Combination of Resistances) | Video #6 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 07

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Equivalent Circuits) | Video #7 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 08

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Series and Parallel Combinations of Cells) | Video #8 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 09

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Kirchhoff's Laws) | Video #9 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lecture 10

Current Electricity Class 12th Physics Video Lectures For Neet exam In Delhi NCERT Book CBSE Syllabus Online Neet Coaching

Current Electricity (Wheatstone's Bridge, Meter Bridge and Potentiometer) | Video #10 | Neet Physics

Class 12th Physics Video Lecture

Online Neet Coaching

Watch Video Watch Video-Physics Video Lectures for neet - online neet coaching

Video Lectures For Current Electricity for NEET Exam

Overview

NEET Class 12 Physics NCERT Chapter 3 Current Electricity

In this video, we will cover:

1. Electric Current

2. Important points of Electric Current

3. Current Density

4. Drift Velocity

5. Relaxation Time

6. Ohm’s Law

7. Resistance and Resistivity

8. Conductance & Conductivity

9. Vector form of Ohm’s Law

10. Temperature dependence 0f Resistivity

11. Important points related to resistivity

12. Current Electricity NEET Concepts

13. Current Electricity NEET

14. NCERT Class 12 Physics Chapter 3 NEET Concepts

15. Current Electricity NEET for 2026-2027

16. NEET Physics Concepts

17. Current Electricity NEET

18. Current Electricity NEET Coaching

19. Current Electricity NEET 2026-2027

20. NEET from Chapter 3 Class 12 Physics

21. Neetbharath.in NEET pe Jeet LH Physics

22. Physics for NEET 2026-2027

23. NEET Class 12 Chapter 3 Physics Current Electricity

24. NEET Current Electricity Chapter 3 Class 12 Physics

25. Class 12 Chapter 3 Current Electricity NEET Coaching

26. Current Electricity NEET Class 12 Chapter 3 Physics

27. FREE NEET Current Electricity

28. FREE of Cost NEET Coaching 2026-2027

29. NEET Physics

30. Neetbharath.in NEET Physics

31. Current Electricity NEET Questions for 2026-2027

32. Questions from NEET Current Electricity

33. NEET Current Electricity

34. Current Electricity NEET Basic Concepts

Chapter 3 Current Electricity Class 12 NEET Physics deals with:

We are going to learn about how the charges which are in motion constitute the current, to study how current is used in our daily life.

For example: -

Glowing of bulb by switching on and off the switch.

All the electrical appliances work when the current passes through them.

Washing machines, iron box,battery,TV,laptop and so on.

In this chapter we will be able to give answers for the following questions :-

How electric current is produced by the movement of charges?

What are the different properties of current?

What constitutes the electric current?

What are the different laws which govern the electric currents?

Electric Current

Electric current is defined as flow of electric charge.

It is measured as rate of flow of charge. It means how much charge is flowing with respect to time. For example consider a charge of 20Coulomb flowing per second. Then the current will be 20Coulomb/sec.

Electric current is denoted by I.

It is written as I=dQ/dt,where dQ is rate of change of charge with respect to time.

I unit is Amperes (A).

Direction of current determines from where the current originated and where it will terminate.

It can be categorised into 2 ways:-Electronic and Conventional Currents.

Electronic current

The electronic current is the flow of current in the direction of flow of electrons.

Conventional current

The current constituted by the positive charges and opposite to electronic current. This is known as conventional current.

The conventional current direction is considered whenever we consider the direction of current.

The direction of current is opposite to the direction of flow of electrons.

In any circuit the current is assumed to flow from positive end to negative end.

Definition of Ampere:-

1 Ampere is unit of measurement of rate of electrons flow or current in an electrical conductor.

It represents one coulomb of electrical charge (6.24 x 1018 charge carriers) moving past a specific point in one second.

Mathematically: - I=dQ/dt

Consider 1A =1C/1sec; where Unit of charge is coulomb and time is sec.

=> 1A is the amount of current when 1C of charge (i.e. 6.24x1018 electrons) pass through a point in 1 second.

You can practice DPPs, Download PDF of Solutions of DPPs, Revise notes for NEET Class 12 Physics CHAPTER 3 Current Electricity.

Feel free to take a test on Class 12 Current Electricity CHAPTER 3 NEET Physics, and test your understanding.

If you liked our content on Current Electricity NEET Physics CHAPTER 3 Class 12, SHARE with your friends!

All About: Current Electricity NEET Physics NEET CHAPTER 3

NEET Physics seems to be a quite difficult subject for a lot of students. But, if you get a very good conceptual understanding of the subject, it can be very interesting for you. We, at Neetbharath Tutorials Delhi, will give our best to make NEET Physics Current Electricity NEET CHAPTER 3 super-duper easy for you. Learn about Current Electricity NEET Physics in detail with experts at neetbharath.in is what we promise. Learning is a lifelong process. As a student, your focus should always be on learning new facts, concepts and tricks so that you can apply them in real-life scenarios. If your conceptual understanding is clear, you will anyway perform well in your exams. So, please do not just study for the fear of exams or just to score marks, instead learn for the love of learning. We have seen many students mugging up concepts without understanding, which, in turn, makes the subject more difficult and boring for them in the future. Always remember, if your basics are strong, you will be able to understand even the most complex concepts.

We aim at making learning fun as well as engaging for you with our complete end-end learning content with Current Electricity NEET Physics Best videos, NEET pdf download, Notes, complete syllabus of the textbook, tests, and Practice Questions. neetbharath.in (formerly called ExamFear Education) is a Free Education platform with more than 10,000 videos on Physics, Physics, Maths, Biology, English, Science experiments, tips & tricks, and motivational videos for Classes 6 to 12, NEET, JEE. Learn for Free!

We, at Neetbharath Tutorials Delhi, will provide you with the best quality videos on NEET Physics Current Electricity with special focus on concepts and a lot of examples, also you can download pdf. Not just that, a quick easy-to-refer and understand Current Electricity NEET Physics NEET CHAPTER 3 Notes, based on the revised NCERT textbooks. You can completely rely on the study materials created by our experts and can definitely score very well in your exams. You also have the option to download pdf as well as complete all topics of the textbook. All of these mentioned above will be accompanied with:

  • NEET Physics Current Electricity NEET CHAPTER 3 DPPs: A set of 20 questions from each chapter for you to attempt and check your understanding. Solutions are also available and can be downloaded in pdf format. Download Current Electricity NEET Physics NEET CHAPTER 3 DPPs solutions PDF for free. Practice these questions once you have watched the videos of the chapter; try to answer on your own. Once done, refer to the solutions to check if you were right or not. This would improve your problem-solving skills as well as help you revise topics you are less confident with. In fact, our research says that the majority of the students feel that their concepts are clear while attending a class or watching a lecture video. But it is during solving a problem or numerical that they truly get to know if they have understood the concept or not. Therefore, we strongly recommend you to solve the DPPs as soon as you have watched all the videos of that chapter.
  • NEET Current Electricity Online Tests: For every chapter, you can take a test of 10 Multiple choice questions. Correct answers along with explanations will be provided after you submit the test. A set of new 10 questions will appear when you try to attempt the test for the same chapter again. This will help you to revise your concepts on Current Electricity NEET Physics. Self-evaluation is one of the best ways for you to understand how much clarity you have got on the concepts of that topic. Based on where you are getting stuck, you can give extra focus on those topics. Taking tests frequently always helps you improve your speed and accuracy.
  • Current Electricity NEET NEET solutions: All questions from NEET textbook are solved in detail, along with video solutions for each question. Download Current Electricity NEET NCERT solutions PDF for free. Students often get stuck while solving the questions in the exercises of NEET textbook. You can watch the NEET solutions in the form of videos with our experts, and can also refer to pdf format on our website as well as app. If you are a student of CBSE or preparing for exams for NEET, JEE, Civil services, NDA etc. NEET textbooks are very important for you. Please note that we have uploaded videos as per the Revised NEET textbooks (2023-24). Therefore, you can completely rely on the content on our website/app.
  • NEET Physics Sample papers: You must attempt a couple of our specially curated sample papers before appearing for your exam. This will boost your confidence and also help you practice. Once you have completed the syllabus, it is very important for you to solve Sample papers. In an exam-like environment, solve the sample paper. Once done, check the answers and understand which are your strong areas and which are the weaker ones. The sample papers are created based on the complete syllabus of a particular subject.
  • NEET Physics Previous Years’ Questions: Questions that appeared in the last 5-7 years along with detailed solutions for better understanding for the entire NEET Physics syllabus. This is a very critical step towards your preparation for any examination. This gives you a fair idea of what kind of questions are asked in that particular exam. It also helps you understand the important topics from where the majority of questions are framed. We will provide you with Previous years’ questions of Class 10 and Class 12 NEET exams, as well as NEET, JEE, both in video format as well as PDF format.
  • Last but not least, We, at Neetbharath Tutorials Delhi, are on a mission to Neet Education.

If you like our content, Spread the word!

Tips for Students
  1. Never miss a video on Current Electricity NEET Physics
  2. Make your notes while watching Current Electricity Class 12 NEET Concept Add on Electron, Proton & Neutrons, Atomic Models| Physics
  3. Make a note of all your doubts as you watch Current Electricity Class 12 NEET Concept Add on Electron, Proton & Neutrons, Atomic Models| Physics, and ask them in the “Ask Question” section of neetbharath.in
FAQs
  1. How should I prepare for my NEET Physics exam?
    • Watch all our Videos, Notes, NEET Solutions, DPPs for NEET Physics
    • Download PDF of Solutions, complete syllabus of textbooks is covered in the videos
    • Attend LIVE classes to ask your doubts on NEET Physics
  2. Can I crack NEET/JEE/Board exam using Neetbharath Tutorials Delhi?

    Of course, YES! If you are determined to crack NEET, you can at ease do that with neetbharath.in

    • Watch NEET Videos on Physics, Physics, Biology
    • Ask your doubts in NEET/JEE/Board exam LIVE classes
    • Refer Notes, DPPs, Online Tests, Practice questions, sample papers, DPPs for NEET
  3. Can I get a good score in NEET Physics board exam if I study only from Neetbharath Tutorials Delhi?

    Yes, you can. Refer Current Electricity NEET Physics NEET CHAPTER 3 videos, notes, tests, Daily practice problems, questions, sample papers. Similarly, cover all chapters of the complete syllabus of NEET for NEET Physics

  4. How to make use of Neetbharath Tutorials Delhi the best possible way to understand Current Electricity NEET Physics NEET CHAPTER 3?
    • Step 1. Watch all videos, without skipping any video for Current Electricity NEET Physics
    • Step 2. Ask your doubts in Ask questions section of neetbharath.in
    • Step 3. Try DPPs, Revise notes, Download PDF for DPPs solutions, refer NEET solutions for Current Electricity NEET Physics
    • Step 4. Take online test, sample paper for Current Electricity NEET Physics
  5. Can I ask my doubts on Neetbharath Tutorials Delhi?

    Yes. You can ask your doubts in the Ask Question section of neetbharath.in. Alternatively, you can also ask questions on our Android Neetbharath Tutorials Delhi app. We will try to answer your questions within 24 hours.

  6. Are all content on Neetbharath Tutorials Delhi free? or some courses are paid as well?

    Neetbharath Tutorials Delhi is a Free learning platform. Neetbharath Tutorials Delhi provides the best videos, notes, pdf, tests, practice questions, DPPs absolutely free of cost. Hope you have watched Free videos on Current Electricity NEET Physics. Did you like them? Neetbharath Tutorials Delhi

If you like the video on Current Electricity Class 12 NEET Concept Add on Electron, Proton & Neutrons, Atomic Models| Physics

Current Electricity FAQs

How many Video Lectures are there for Current Electricity?▶

neetbharath.in offers 20 free NEET Video Lectures for Current Electricity, each with 10-20 questions—200-300 total. Crafted from 25 years of NEET trends, they cover all 2-3 questions this chapter brings to NEET Exam!

Are the NEET Video Lectures free?▶

Yes, all 20 Current Electricity NEET Video Lectures are 100% free—no fees, no catch. Expert-designed with 25 years of NEET insights, they’re open to all aspirants at neetbharath.in.

What topics do these Video Lectures cover?▶

Our 20 NEET Video Lectures span Current Electricity’s syllabus: atomic models (Bohr, Rutherford), quantum numbers, spectral series (e.g., Balmer n₂ = 3 to n₁ = 2), de Broglie wavelength, photoelectric effect—everything NEET Exam tests.

Do the Video Lectures come with solutions?▶

Absolutely! Each of our 20 NEET Video Lectures includes instant, detailed solutions—e.g., calculate Bohr energy (Eₙ = -13.6 Z²/n²) for He⁺ or spectral wavelength. Learn and fix mistakes fast.

Can I practice under NEET exam conditions?▶

Yes, our 20 timed NEET Video Lectures mimic the real exam—45 Physics questions, ~1 minute each. Perfect for mastering Current Electricity’s 2-3 questions under pressure.

Are these Video Lectures updated for NEET Exam?▶

Definitely! Our 20 NEET Video Lectures are refreshed weekly for NEET Exam, focusing on Bohr’s model, quantum numbers, and more—no syllabus cuts noted, just pure numerical and conceptual prep.

What’s Current Electricity’s weightage in NEET?▶

Current Electricity carries 2-3 questions (8-12 marks) in NEET’s 180-mark Physics section. Our 20 mock tests ensure you nail every point with targeted practice.

How do 25-year trends shape these tests?▶

Our experts analyze 25 years of NEET questions—like 2022’s quantum number set or 2023’s photoelectric V₀—to craft our 20 Video Lectures, matching the exam’s style and difficulty.

How can I ace Current Electricity with these tests?▶

Practice all 20 NEET Video Lectures (200-300 questions)—focus on Bohr energy, spectral lines, and quantum rules. Review solutions (e.g., λ = h/mv errors), and build speed with our timed format.

Why pick neetbharath.in for Current Electricity?▶

neetbharath.in delivers 20 free NEET Video Lectures for Current Electricity, each with 10-20 questions, rooted in 25 years of NEET data. Free, updated, and expert-crafted—they’re your edge for NEET Exam 2-3 questions.

Class 12 Physics Current Electricity NCERT CHAPTER 3


Revision of Class 12 Physics Current Electricity is a crucial aspect of effective learning. Revision plays a vital role in the learning process and is especially important before exams. Here are some key points you can consider emphasizing in your content:

  1. - Retention and Memory: Regularly reviewing and revisiting the material of Class 12 Physics Current Electricity helps reinforce the concepts in student's minds. It strengthens memory pathways, making it easier to recall information during exams and beyond.
  2. - Consolidation of Knowledge: When you revise notes, you are essentially consolidating your knowledge. This means connecting new information with what you already know, making the overall understanding more robust.
  3. - Identifying Knowledge Gaps: Revision allows students to identify any gaps in their understanding or areas where they need further clarification. This gives you a chance to seek help or delve deeper into those topics. For detailed understanding, you can always refer to the videos of Current Electricity Class 12 Physics NCERT CHAPTER 3 on neetbharath.in
  4. - Building Confidence: As you revise Current Electricity Class 12 Physics and become more familiar with the content, your confidence in your abilities grows. Confidence is a crucial factor in exam performance as it reduces anxiety and allows you to approach exams with a positive mindset.
  5. - Different Revision Techniques: Use a variety of revision techniques such as summarizing notes, creating flashcards, practicing past papers, discussing concepts with peers, and teaching others. Different techniques work for different students, and it's essential to find what suits you the best. You can also attend the LIVE Revision classes on neetbharath.in or watch the LIVE Revision Race videos of Neet Bharath Tutorials on Current Electricity Class 12 Physics NCERT CHAPTER 3.
  6. - Spacing Effect: Spacing out revision sessions over time, rather than cramming all at once, has been shown to improve long-term retention. Create a revision schedule leading up to the exams to allow for spaced practice.
  7. - Regular Revision over Cramming: Regular and consistent revision throughout the academic year is very important. Waiting until the last moment to cram everything can be overwhelming and less effective than spaced-out revision.
  8. - Self-Assessment: Assess your understanding periodically through quizzes or self-tests. This helps you to gauge your progress and identify areas that need further attention. Refer Class 12 Current Electricity Online Tests.
  9. - Balanced Approach: Remind students to strike a balance between revision and other activities. Adequate rest, exercise, and relaxation are essential for optimal learning and performance.
  10. - Seeking Help: If you face difficulties during the revision process, Refer the videos of Class 12 Physics Current Electricity. Clearing doubts promptly is crucial for a better grasp of the subject matter. You can always ask your doubts on Current Electricity Class 12 Physics NCERT CHAPTER 3. “Ask a Question” section of neetbharath.in

By highlighting the benefits and strategies of effective revision, you can approach your studies more mindfully and achieve better results in your exams. Best of luck bachhon!

Class 12 Physics seems to be a quite difficult subject for a lot of students. But, if you get a very good conceptual understanding of the subject, it can be very interesting for you.

We, at Neet Bharath Tutorials, will give our best to make Class 12 Physics Current Electricity NCERT CHAPTER 3 super-duper easy for you.

We aim at making learning fun as well as engaging for you with our complete end-end learning content with Current Electricity Class 12 Physics Best videos, Notes, NCERT pdf, NCERT complete syllabus, tests and Practice Questions.

Always remember, it is very important to study with full concentration during Revision. Here are a few tips for you on how to revise with full focus:

  1. - Create a Distraction-Free Environment: Find a quiet and comfortable place to study where you can minimize distractions. Turn off or silence your phone, log out of social media accounts, and inform others around you that you need uninterrupted study time. A dedicated study environment will help you focus better.
  2. - Set Specific Goals: Before starting your study session, set clear and achievable goals. Break down your study material into smaller tasks, and plan what you want to accomplish during each session. Having specific goals will give you a sense of direction and purpose, making it easier to concentrate.
  3. - Use the Pomodoro Technique: The Pomodoro Technique is a time management method that involves studying in short, focused intervals, typically 25 minutes, followed by a short break of 5 minutes. After completing four sessions, take a longer break of around 15-30 minutes. This technique can improve focus and productivity by providing regular breaks to recharge.
  4. - Stay Organized: Keep your study materials, notes, and resources well-organized. Having everything you need at hand will save time and reduce distractions caused by searching for materials. Use color-coded folders or digital tools to maintain a structured study system.
  5. - Practice Mindfulness and Meditation: Before you begin studying, take a few minutes to practice mindfulness or meditation. Deep breathing exercises and clearing your mind of distractions can help you approach your study session with a calm and focused mindset.

- Remember, studying with full concentration is a skill that takes time and practice to develop. If you find your mind wandering during study sessions, gently bring your focus back to the task at hand and be patient with yourself. With consistent effort, you can improve your ability to concentrate and make the most of your study time.

Last but not the least, To get the best hold on Class 12 Physics Current Electricity Book CHAPTER 3. Do not forget to check out:

  • - Current Electricity Class 12 Physics Best videos
  • - Current Electricity Class 12 Physics NCERT Solutions
  • - Class 12 Physics Current Electricity Revision notes
  • - Current Electricity Class 12 Physics DPPS, Download PDF of solutions
  • - Class 12 Physics Current Electricity Online Tests
  • - Class 12 Physics Sample papers


Reader Interactions

Leave a Reply

Required fields are marked *