Na jaane kitne bacho ki zindagi sawari hai sir aapki kitaab ne. The legend! Lots of respects, sir. ❤️ Jiyo hazaro saal. ❤️ Lots and lots of gratitude, teacher.
@@ayushbarman6903 Bhai ye kitaab agar ek baar dhang se mann laga kr padh li na, physics bohot sudhar jati hai. Personal experience. The way of writing and explaining things is simply the best.
But Indian's don't understand the great HC Verma....they are not interested in phy.6....they are more interested in jobs and all the subjects are just their way through....that's what Walter Lewin(former phy.6 professor at MIT) said....one of his Indian subscribers said when asked how he solved the question so fastly...."We Indians have a "formula" for every question and we just have to put values into it to solve it"....he had given a week time for his subscribers to solve and and he wanted them to derive the required formula....and this reflects why current India is scientifically so backward despite its large population.....
Altough I didn't thought about this while going through this formula. Still it's immensely useful for students like me. Kudos to the guy who asked this beautiful question as well as our hard working sir who beautifully illusrated this.
Sir ,,I had the same doubt ,,but I couldn't find the answer from anywhere even from ur physics book ,,then I came to RUclips and watch many many many videos but I didn't find ,,,but now I find ur video and get the answer,, really sir ,,very happy 😊,,, great satisfaction
I even can't imagine what would be the number of students who would start loving physics after solving sir's books. And I am really proud to be one of them❤ #FANS OF HC.VERMA
Thank you very much Verma sir. I have been searching for the answer to this question for a long while. It took my sleep away. I asked some of my teachers, none them could give me a satisfactory answer. Thank you so much for clearing this concept. This is what I assumed from reading Fundamentals of Physics and Concepts of Physics but my teacher taught it wrong. You will see a lot of books and a lot of teachers proving it the wrong way.
17 uneducated were spotted out there.. i don't even dare to hit like button, because Verma Sir is beyond any appreciation.. the only thing that made me driven to fall in love with physics - his Concept of Physics Vol I & Vol II unfortunately I got know about these books later my 12th exam.. no one gonna believe that I got only 35% of marks in physics.. & presently I am a chartered electrical engineer (b.tech) one needs to feel physics instead of thorough read out only.. you never gonna make it out.. Physics is a kind of subject where you need to grow your presence of mind & sense of maturity.. when you'll get start to realize & anticipate the facts of those theories & hypothesis, it won't demoralize you ever.. PHYSICS IS REALITY, PHYSICS IS EVERYTHING, PHYSICS IS THE AUTHENTICITY 📝💕 Edited: shockingly that number 17 has become now 185 ! ! !
I think If you love physics that's mean you love astronomy and I recommend you to try universe send box 2 simulator, it is blow your mind and also see cosmos series.
I wasted lot of time for this particular topic in class 12. Had this confusion for so long. The more I read from different sources (i read from COP of course, halliday resnick, ncert text, dc pandeys text, Olympiads books, coaching materials, my school text nowhere it is mentioned) the more I got confused right here. Later I learned it with the help of an intuition that "in the direction of electric field potential decreases". This actually helped me use the formula in calculations. Thank you for this sir, i wish somebody would have told me about your email and I had mailed you this question.
सर आप एक संत है physics को आपने इतना सरल कर दिया कि उसको शब्दो मे बयान नही किया जा सकता ज्यादातर teachers सिर्फ notes बनवाते है जैसे physics नही history पढा रहे़...और आपने बताया कि physics को real lifeमे कैसे use करना है।
Thanking you Sir 🙏, Whenever i feel that this chapter is tough for me then I put your book is my now 😂 on the table and started reading then aftermath I understand too many things and i started to solve problems then it would become too much easy. So, Thanks a lot sir for your support 🎉🎉 .. Lots of Love from my and my friends side 🙏🙏🙏🙏
I have a different explanation to it. I was suffering through this problem for years and finally figured it out a year back. So I explain now Potential at a point is work done per unit positive test charge in bringing is from infinity to that point by external agency. Now the charge q1 is repelling the charge q2 towards right , ur force must bring the charge towards q1. So ur force which is ext agency force is equal in magnitude to force of q1 on q2 is towards left and dx is towards left Just take dot product. F.dr = Fdxcos(theta) = Fdx = kq1q2/r² × dx Now angle is zero and dxcos180 = -dr as dr is is always along the increasing direction of r Integrate within limits infinity to r0 and u will get right answer What I have done here is that m not even considering the direction of force due to field of q1 Since potential has nothing to do with field force and everything to do with my force exactly opposite to field force I am simply finding work done by my force.
@@electronicsbasics tnx for the telling me. Actually I always do this procedure for general case means when there is an angle between ext force and path chosen to travel the charge. So I take the path chose. As dx and when dot product is solved it becomes Fdxcostheta. Now this this dxcostheta is dr and costheta takes care of sign. Here since the path was in the line of r I missed the dx. Now read it u will find it correct
@@electronicsbasics u do one thing. Take path such that electrostatic force and path have acute angle between them Now from the path drop a perpendicular on line of force. Then dxcostheta = dr Now if u take ext force in same situation. Dxcostheta will ramain dr but angle will be cos(180-theta) which will be -cos(theta) So we wil get equation -fdr
Method 1 Tak leftwards direction positive then dr is Positive, limits from -infinite to -r ( because point is in negative side of origin) , external force is in positive direction, do it is positive, Second method If we take rightwards direction positive Take modulus dr instead of dr, now modulus dr is -dr because r is decreasing, external force in negative direction limits infinite to r Method 3 Find work done to take q2 from r to infinite, then required work is opposite to this work, so your answer is the negative of this work, In short, first fix origin and positive direction we assume, if dr in the direction of given limits then take dr otherwise take - dr, Hope it will help
Hello sir... Pranam. Can we say like this?When we are bringing a charge from infinity to a given point of we calculate work done due to the electrostatic force of repulsion,then F and dr are opposite to each other ,hence the angle between them is 180°. So dot product becomes -Fdr. And finally we get the desired result. Similarly if the source charge is negative then F and dr will be in the same direction and hence we get only Fdr. And by integrating it form infinity to r we get negative value of potential.
No you have calculated work done by conservative force. Also potential energy=work done by external force= -(work done by conservative force). The problem isn't actually with the physics concept, but due to our limited knowledge of integration
Dear sir, I have read in a book that dx is not just increment, but, it represents change in the variable ( may be increment or maybe deferment in that variable)
Sir I have a question . Here dr taking as a Very small element that's why dr takes as always positive but dr also a vector quantity and we all know that vector quantity can positive or negative both in this situation we can take dr with a negative sign ..🙏🙏🙏🙏
Sir please solve this Two point charges each having charge q are placed on the x-axis at x = -a and x = +a as shown in figure. (a) Plot the variation of electric field (E) on the x-axis (b) Plot the variation of electric field (E) on the y-axis. (c) Find the position on the y-axis where electric field is maximum.
Sir, integration is from infinity to r & not from -infinity to r. Second, it is the choice of origin that makes (r+dr - r ) as positive. We can also take our origin at infinity or any other point. Taking scalar product of two vectors quantities will reslove the signs.
It is good that you raise such questions. Students should think on their own and question what others say, otherwise science would have stopped long ago. You will go a long way if you keep working hard like this.
And sir dr is the infinitesimal change in r. So for increasing value of r, dr also increasing and for decreasing r it will decreasing. So negative dr doesn't mean it's negative. Its just mean the value decreasing. Why I tell you bcz if we use your technique to calculate the potential from a point to infinity then there is no negative Sign for potential, that leads to confusion for the reliable of this technique. Bcz magnitude of force is always take positive, dot product is on this derivation. I think (-dr) is solve the problem for all when we see there is decreasing of r. Sir I am not meant to disrespect you but your explanation leads to confusion in my mind. Kindly rply me. And clear my doubt
@@You-ul7dr yes side hero I know it's a vector. But what sir did I just think f we can't take(-F) bcz dot product F.dr=f magnitude multiply dr magnitude. But sir take - F after dot product. Can hero explain this. And thanks to call me hero.
@@You-ul7dr and hero by defination we take dr is the increasing order of r. So don't try to misguide that negative or positive or vector. Try to understand what I means.
Because of this +,- and integration paradox....god knows how people many people have developed low confidence...some teacher say it as if it is for granted.....i am truly grateful to you sir for saving me from this dilemma....trully greatful..
The correct explanation is that (F) (dr) cos180°= - (F) (dr) Force vector and dr vector makes angle 180° with each other.work is defined as dot product of force vector and dr vector.Actually we have taken (dr) as a very short distance on which charge have moved by force(F) . Here (F) is not constant because force is dependent on one variable which is (r). So we have to find integral of (dw). Otherwise we can normally multiply force vector and radius vector. Which is(F) (r) cos180°. The whole conclusion is that here (dr) is very short distance, and there is a force and work done formulae is (F) (dr) cos180°= - (F) (dr)
Absolutely saluted Sir ji. Great to see you in RUclips. Please make more videos so that we can enrich our little brain from the vast knowledge of yours. Regards and pranam Sir ji 🙏🏾♥️🤘🏾
Sir what is relation between potential difference,voltage and electric field we are saying ef is force on unit charge but distance also make different readings
I m also confused in the same problem of dr
And finding it from many books
Bt at last ur vedio helps me a lot
Na jaane kitne bacho ki zindagi sawari hai sir aapki kitaab ne.
The legend! Lots of respects, sir. ❤️
Jiyo hazaro saal. ❤️
Lots and lots of gratitude, teacher.
Sawari hai jinkopadhai se pyaar h ....aur bigadi h jinko padhai se nafrat h .....especially physics ....😂😂😂😂😂😂😂
@@ayushbarman6903 Bhai ye kitaab agar ek baar dhang se mann laga kr padh li na, physics bohot sudhar jati hai. Personal experience. The way of writing and explaining things is simply the best.
@@sanketpatil4039 ha wo to h .....hm bas ek practical baat bola ...
But Indian's don't understand the great HC Verma....they are not interested in phy.6....they are more interested in jobs and all the subjects are just their way through....that's what Walter Lewin(former phy.6 professor at MIT) said....one of his Indian subscribers said when asked how he solved the question so fastly...."We Indians have a "formula" for every question and we just have to put values into it to solve it"....he had given a week time for his subscribers to solve and and he wanted them to derive the required formula....and this reflects why current India is scientifically so backward despite its large population.....
Excellent
Sir, you are a big source of inspiration for billions of people l.
You are really a legend.
Salute to this man.
Altough I didn't thought about this while going through this formula. Still it's immensely useful for students like me. Kudos to the guy who asked this beautiful question as well as our hard working sir who beautifully illusrated this.
Sir please please please 1000000000000 times request you to please make a video on potential difference
Sir ,,I had the same doubt ,,but I couldn't find the answer from anywhere even from ur physics book ,,then I came to RUclips and watch many many many videos but I didn't find ,,,but now I find ur video and get the answer,, really sir ,,very happy 😊,,, great satisfaction
I even can't imagine what would be the number of students who would start loving physics after solving sir's books.
And I am really proud to be one of them❤ #FANS OF HC.VERMA
There is so many teachers as a student of H C verma sir
Sir after concept of physics 1nd 2 it is a great initiative. Thank you so much sir it is an honour of being your student. ☺☺
Thank you very much Verma sir. I have been searching for the answer to this question for a long while. It took my sleep away. I asked some of my teachers, none them could give me a satisfactory answer. Thank you so much for clearing this concept. This is what I assumed from reading Fundamentals of Physics and Concepts of Physics but my teacher taught it wrong. You will see a lot of books and a lot of teachers proving it the wrong way.
Its an honor that we are studying from a living legend 😌😌
I didn't understand a word altogether but liked the video for supporting the legendary man's effort .
Sir you are the real genius for student life
हम भाग्यशाली हैकी आपके विद्यार्थी होने का मौका मिला 🙏🙏🙏
17 uneducated were spotted out there.. i don't even dare to hit like button, because Verma Sir is beyond any appreciation..
the only thing that made me driven to fall in love with physics - his Concept of Physics Vol I & Vol II
unfortunately I got know about these books later my 12th exam..
no one gonna believe that I got only 35% of marks in physics..
& presently I am a chartered electrical engineer (b.tech)
one needs to feel physics instead of thorough read out only..
you never gonna make it out..
Physics is a kind of subject where you need to grow your presence of mind & sense of maturity..
when you'll get start to realize & anticipate the facts of those theories & hypothesis, it won't demoralize you ever..
PHYSICS IS REALITY, PHYSICS IS EVERYTHING, PHYSICS IS THE AUTHENTICITY 📝💕
Edited: shockingly that number 17 has become now 185 ! ! !
Itna likhne ka time tha
@@ramnivaskumar8732 yes pretty much.. i thought it will motivate mediocre aspirants..
I think If you love physics that's mean you love astronomy and I recommend you to try universe send box 2 simulator, it is blow your mind and also see cosmos series.
Welcome to a beautiful Cult. 🤘😂
I was thinking the same who are they to unlike verma sir my god
I wasted lot of time for this particular topic in class 12. Had this confusion for so long. The more I read from different sources (i read from COP of course, halliday resnick, ncert text, dc pandeys text, Olympiads books, coaching materials, my school text nowhere it is mentioned) the more I got confused right here. Later I learned it with the help of an intuition that "in the direction of electric field potential decreases". This actually helped me use the formula in calculations. Thank you for this sir, i wish somebody would have told me about your email and I had mailed you this question.
That actually is really smart
Bro what are you doing now?
@@vishishtmishra9082 hi bro. Im doing my second year in mechanical engg in nit.
@@aniketbiswas9885 I didn't understand this can you explain , please 🙏
The same question has been my problem since i first studied that.
Now its been clear to me how its done.
Thank you so much sir,
Your truly zeeshan.
easily understanding your lectures ,fine expressions.
सर आप एक संत है physics को आपने इतना सरल कर दिया कि उसको शब्दो मे बयान नही किया जा सकता ज्यादातर teachers सिर्फ notes बनवाते है जैसे physics नही history पढा रहे़...और आपने बताया कि physics को real lifeमे कैसे use करना है।
Very nice
thanks sir for this video.
and again thanks for the book you published it is really helping me , now i am capabale of cracking jee !
Thanking you Sir 🙏,
Whenever i feel that this chapter is tough for me then I put your book is my now 😂 on the table and started reading then aftermath I understand too many things and i started to solve problems then it would become too much easy. So, Thanks a lot sir for your support 🎉🎉 ..
Lots of Love from my and my friends side 🙏🙏🙏🙏
Daaammmm......he is like the god of physics for all science students
Thank you very much sir.I had the exact same doubt and was highly frustrated even after referring many textbooks.thank you sir
I have a different explanation to it. I was suffering through this problem for years and finally figured it out a year back.
So I explain now
Potential at a point is work done per unit positive test charge in bringing is from infinity to that point by external agency.
Now the charge q1 is repelling the charge q2 towards right , ur force must bring the charge towards q1. So ur force which is ext agency force is equal in magnitude to force of q1 on q2 is towards left and dx is towards left
Just take dot product.
F.dr = Fdxcos(theta) = Fdx = kq1q2/r² × dx
Now angle is zero and
dxcos180 = -dr as dr is is always along the increasing direction of r
Integrate within limits infinity to r0 and u will get right answer
What I have done here is that m not even considering the direction of force due to field of q1
Since potential has nothing to do with field force and everything to do with my force exactly opposite to field force I am simply finding work done by my force.
Your answer will be negative
@@electronicsbasics tnx for the telling me. Actually I always do this procedure for general case means when there is an angle between ext force and path chosen to travel the charge.
So I take the path chose. As dx and when dot product is solved it becomes Fdxcostheta.
Now this this dxcostheta is dr and costheta takes care of sign.
Here since the path was in the line of r I missed the dx.
Now read it u will find it correct
@@electronicsbasics u do one thing. Take path such that electrostatic force and path have acute angle between them
Now from the path drop a perpendicular on line of force.
Then dxcostheta = dr
Now if u take ext force in same situation. Dxcostheta will ramain dr but angle will be cos(180-theta) which will be -cos(theta)
So we wil get equation -fdr
how can infinity be negative
@DhruvK13 tx
Sir its a kind request please change the video title so people with this doubt can find this video easily, cause i acquired this after months
Thank you so much sir. Some teachers are teaching it wrong saying Force and displacement are in opposite direction that is why we take -ve sign.
So is it wrong to take *F.dx* = F.dxcos180 ??
This is what we call a great teaching 😊
I'm also a big fan of HC Verma sir
Thank you sir...please keep guiding us in the pursuit of knowledge
Sir your way of teaching physics is very nice...matlab aap ek flow mai Bolte hai....thanks sir .. you may long live......😃😃😃😃😃😃😃😃😃😃😃😃😃😃😃😃😃😃
Mera 11th hai is year mujhe ye bikul samjh nahi aaya but I love you sir and your style of teaching😇😇😍
m=Most respected teacher in the education FIELD
.
Question is good
But explanation is verryyy excellent
Excellent sr
Great sir your presence of mind awesome 👌
Sir i great salute to you because iss age m bi app pada rahe hoo
Awesome professor, thank you sir!
Salute to the person who asked this wonderful doubt.....🙏🙏🙏
great explanation sir really very helpful please keep making videos 👍👍👍👍🙏🙏😊😊👏👏
Sir...really u are 21th century Einstein
Sir u are very intelligent........ proud of you
Thanks sir u always try to clearing our doubt through simple way ,love u sirr❤️
Wow. He explained this so easily!
Sir you make physics easy and enjoyable.😄😄😄😄😄
Thank you so much sir , you made physics easy and interesting for us . Thank you
Good thing
Sir you are motivation for the students
Sir ur teaching style so unique
Thanks sir for this small but main point..........it was really need for me to understand it I was confused in it...
I like yr teaching style 🙏🙏🙏🙏🙏
Same doubt arose in my mind....thanks a lot for clarification
Feeling better now sir this has been troubling me for days
Thank you sir for giving this necessary information.
Method 1
Tak leftwards direction positive then dr is
Positive, limits from -infinite to -r ( because point is in negative side of origin) , external force is in positive direction, do it is positive,
Second method
If we take rightwards direction positive
Take modulus dr instead of dr, now modulus dr is -dr because r is decreasing, external force in negative direction limits infinite to r
Method 3
Find work done to take q2 from r to infinite, then required work is opposite to this work, so your answer is the negative of this work,
In short, first fix origin and positive direction we assume, if dr in the direction of given limits then take dr otherwise take - dr,
Hope it will help
Sir I am very glad to listen to ur classes
Thanks alot sir I was confused about this concept from 11th thaaaaaanks
Excellent lecture Sir. Regards
Got it.
Excellent explanation sir.
#RESPECT
Thanks sir for your efforts ❤
Thank you so much sir ❤❤❤❤❤ for the concept
Superb amazing 🙏👍
Hello sir... Pranam. Can we say like this?When we are bringing a charge from infinity to a given point of we calculate work done due to the electrostatic force of repulsion,then F and dr are opposite to each other ,hence the angle between them is 180°. So dot product becomes -Fdr. And finally we get the desired result. Similarly if the source charge is negative then F and dr will be in the same direction and hence we get only Fdr. And by integrating it form infinity to r we get negative value of potential.
No you have calculated work done by conservative force. Also potential energy=work done by external force= -(work done by conservative force). The problem isn't actually with the physics concept, but due to our limited knowledge of integration
Dear sir, I have read in a book that dx is not just increment, but, it represents change in the variable ( may be increment or maybe deferment in that variable)
Sir I have a question . Here dr taking as a Very small element that's why dr takes as always positive but dr also a vector quantity and we all know that vector quantity can positive or negative both in this situation we can take dr with a negative sign ..🙏🙏🙏🙏
dr will always be positive kyoki uski directions ke liye hamne already limits put ki hi hai.
Sir ne yahi toh bataya hai video me!
Video toh dekh lo!
Sir please solve this
Two point charges each having charge q are placed on the x-axis at x = -a and x = +a as shown in figure.
(a) Plot the variation of electric field (E) on the x-axis
(b) Plot the variation of electric field (E) on the y-axis.
(c) Find the position on the y-axis where electric field is maximum.
Thank you sir 🙏🙂
Sir, integration is from infinity to r & not from -infinity to r. Second, it is the choice of origin that makes (r+dr - r ) as positive. We can also take our origin at infinity or any other point. Taking scalar product of two vectors quantities will reslove the signs.
It is good that you raise such questions. Students should think on their own and question what others say, otherwise science would have stopped long ago. You will go a long way if you keep working hard like this.
Abe bhai calculus kaise karega Electric field as a function of r from infinity kaise niklega
Pranam guru dev, I am DM, u r great
Sir you are legend of physics 🙏🙏
Very helpful video thanku sir
Once a legend always a legend
Thnq sir it really helps a lot😘😘😘😘😘😘😘😘😘😘
#priceless
Big fan for your
SIR KE LIYE EK LIKE TO BANTA HAI
to krde hme kio bta rhahai
And sir dr is the infinitesimal change in r. So for increasing value of r, dr also increasing and for decreasing r it will decreasing. So negative dr doesn't mean it's negative. Its just mean the value decreasing.
Why I tell you bcz if we use your technique to calculate the potential from a point to infinity then there is no negative Sign for potential, that leads to confusion for the reliable of this technique. Bcz magnitude of force is always take positive, dot product is on this derivation. I think (-dr) is solve the problem for all when we see there is decreasing of r. Sir I am not meant to disrespect you but your explanation leads to confusion in my mind. Kindly rply me. And clear my doubt
Abe hero vector ki baat hori idhar isliye - dr vector will means it is negative
@@You-ul7dr yes side hero I know it's a vector. But what sir did I just think f we can't take(-F) bcz dot product
F.dr=f magnitude multiply dr magnitude. But sir take - F after dot product.
Can hero explain this. And thanks to call me hero.
@@You-ul7dr and hero by defination we take dr is the increasing order of r. So don't try to misguide that negative or positive or vector. Try to understand what I means.
you have a point bro
Sir , please let us know what is an *Einstein-Rosen Bridge* in your next video tutorial...😁 And also some concepts on *Antimass*
Great sir👌
Amazing sir
Thanks a lot sir for solving that question 🙏
Parnam sir your big fan
He is so simple that anyone can't imagine that he is the H.C.Verma sir
Your book is so awesome
Because of this +,- and integration paradox....god knows how people many people have developed low confidence...some teacher say it as if it is for granted.....i am truly grateful to you sir for saving me from this dilemma....trully greatful..
I am big fan of Sir H cVerma🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
Ye log kon h jo aise video KO bhi dislike krte h ......nhi smjh me aata h too Chor do bhai
Sir make whole syllabus of 11 and 12 once....people will benifit from it for years
He was died
Sir please upload some videos on flux and conductors...it will be a great help....
-a student curious to learn physics
Sir why alph
a particles in Rutherford s experiment didn't act as wave why scattered
The correct explanation is that
(F) (dr) cos180°= - (F) (dr)
Force vector and dr vector makes angle 180° with each other.work is defined as dot product of force vector and dr vector.Actually we have taken (dr) as a very short distance on which charge have moved by force(F) . Here (F) is not constant because force is dependent on one variable which is (r). So we have to find integral of (dw). Otherwise we can normally multiply force vector and radius vector. Which is(F) (r) cos180°.
The whole conclusion is that here (dr) is very short distance, and there is a force
and work done formulae is
(F) (dr) cos180°= - (F) (dr)
Sir force and dr are in same direction I think.....is that true....??
Absolutely saluted Sir ji. Great to see you in RUclips. Please make more videos so that we can enrich our little brain from the vast knowledge of yours. Regards and pranam Sir ji 🙏🏾♥️🤘🏾
Nice video sir ji
You are genius sir
Integration from low to high limit from right the origin is just -ve of integration from high to low limit
I think this concept is used
Am I right ?
Thanks to you sir❣️❣️👍😀😀😀
PW also great 😃😃😃😃
Sir one word for u....legend
Sir .in case ,like charge potential ,and in case unlike charge potential ..if increases or decreases. ..this is Hari from Telangana
Sir why potential is not associated with electric field created by changing magnetic field
because that electric field is non conservative, and potentials are only defined for conservative forces
Sir what is relation between potential difference,voltage and electric field we are saying ef is force on unit charge but distance also make different readings
f 5 volt is energy require to move a chrage particle from a pont a to b if we double the ditance between a to b does volt remain smae
Sir my question is
What is electric potential ? When r=
I am your big fan sir