Potential Difference vs. Electromotive Force - A Level Physics
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- Опубликовано: 22 окт 2024
- This video explains the differences between potential difference and electromotive force for A Level Physics.
This is where it gets tricky! You may previously have used the term 'voltage' but now you need to understand the difference between the e.m.f. of a supply and the p.d. across a component. This also shows you where to put a voltmeter in a circuit and the definitions of all key terms. Please note that this analogy is not perfect, it doesn't really explain how energy can be transferred almost instantaneously or how alternating current works but it's a start.
Electromotive Force: The energy gained per unit charge by charges passing through a supply (from chemical to electrical).
Potential Difference: The energy lost per unit charge by charges passing through a component (from electrical to other forms).
Thanks for watching,
Lewis
This video is recommended for anyone studying A Level Physics in the following exam boards:
AQA
CIE
Edexcel
Edexcel IAL
Eduqas
IB
OCR A
OCR B
WJEC
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This explanation is 100x better than my high school teacher
How could I ever thank you enough, I finally understood Emf. and P.d.
And I'm 19, been through school and so much, but I guess all it required was some unorthodox explanation using Legos 😂👌🏼
What a legend. Everyone else’s explanation is over complicated. Yours is intuitive and complete. Perfect, thank you !
really loved the way you showed it with the help of lego,you made it easier and way more polite(in some ways)
Thank you so much this helped me understand this concept better than 4 other teachers who had taught me this.
Thank you!
I wish more teachers were like you. Thanks a lot for this explanation
Words simply cannot express my gratitude. Thanks for your wonderful analogy and succinct explanation.
You're very welcome
Between 5.00 and 5.03 I said it must go in parallel with the component in the circuit.
How?
You should pin this comment. And your videos are great :)
your explanation are clear and so helpful; thank you so much I don't know what would i have done without them.
HOLY SHIT IN THAT SPAN OF 6 MIN I LEARNT MORE THAN WHAT I HAVE FROM HOURS OF READING MY TEXTBOOK THANK YOU SO MUCH
Magnificent effort for better grasping.........1000 salutes and of course thank you...
Your videos are awesome and very helpful, keep up the good work👌
These videos are superb, keep them coming!
All I could think about the entire video is how similar you sound to Josh from the Sidemen. Great video!
Oh yeah
What a great explanation, the problem is, people always treat EMF and Potential Difference as one thing (Voltage), which makes electricity hard to understand and you feel there is a contradiction. (Ex: they always say that when we have a close circuit we have hight current + voltage is the thing that makes electrons move which means if there is no voltage so there is no current, but in a close circuit as I mentioned the current is very hight but they say the voltage will be 0 !! how we will have current then? but what they mean is we still have EMF the electrons are loaded with energy, but the electrons with a close circuit do not drop this energy since there is no load (which means there is no potential difference, potential difference = 0) and they use Voltage here instead of potential difference.
i thought it was hard.... but you made it very simple... don't know how to thank you.... god bless you!❤❤❤❤❤ THANK YOU SOOO MUCH!
Very nice explanation. Thanks for the video!!
Very understanding way to explain.
Got the idea. The major difference is that the emf is always higher than the potential difference in the ckt what i came to understand from this video.
Thanks a lot
Absolutely wonderful video. Easy to understand analogy. Clears my concept very much. Thank you!
Videos are excellent.Can you make a summary for all the a level physics definitions that need to be memorized, thank you very much.Wish your channel to be better and better.
Brilliant explanation! Thanks!
Thank you so much for this innovative idea.
Finally I get it, cheers boss!
Very good way of visualizing it..thnx dude
Glad you liked it!
This explanation is absolutely brilliant !
Well explained. Thank you.
Thankyou for your explanation...after 3day of my heard work finally with the help of your video i have cleared may concept:)
good attempt to explain the concept
i was really confused about it and was mixing them up thank you for your effort of explaining
these videos are absoluetly brilliant
Thank you - there are now over 500!
Excellent explanation!!
This is so good! Thank you.
thank you this was a great help been stressing for a while and you helped me out !!!!!!!!!!!!
Hi dear Lewis . Thank you for your video . As far as I have learned , electrons ( charge carriers ) do not move so far through a wire. In fact electrons move a very short distance . They actually transfer their electrical field to one another and they move only few centimeters. No electron leaves the conductor . For example in a wire of 1 meter long it may never happen that an electron reaches from one head to the other , because they have a back and forth movement . Is this right ? thanks again for your video .
farthead farthead
Wow great vid and explanation. Thanks
I am 14 and This was so helpful thanks a lot
wonderful video
Let me ask another question I've always had. If we connect only one (positive) head of a power supply to a conductor ,What will happen? I mean what exactly do electrons do ?. Do they still start moving toward the other end of the wire ? Do they accumulate somewhere id. on one end of the wire or what ? Do they receive the electrical field from the power supply and keep transferring it to each other ? thank you
Does the distinction actually matter? One is just voltage source and the other the voltage drop. By definition the potential difference between two points is the voltage. The source anode and cathod has voltage and when the circuit is completed the full voltage of the source goes to the load.
I love you so much for using Legos to help me understand this. Thank you Lewis!
Hello Sir,
Thanks for this helpful video.
But I did not understand what you said between 5:00 and 5:03 where you say " and in order for it to "something" part of the circuit " . What is the word you said mean and what is it?
'basically have no' ^^
i love your teaching style💞❣️❣️❣️❣️❣️
Thank you! 😃
So will the e.m.f provided by the battery have an opposite sign to the p.d measured across the component? Furthermore, if the e.m.f from the battery had exactly the same magnitude as the p.d measured across the component, would the current be zero? That is, the system would be in equilibrium?
It's sooo cuteee I can't!!! But the explanation was excellent! Thank youuuu
thank you
Thanks mate now i get it, great explanation.
Great videos. Please keep making them.
+ModdersApprentice Thanks - hope they're useful.
Bro thank u so much great explanation 😍
Fantastic videos thank you
thank u so much
PD is what we were taught as voltage drop back in the dark ages.
thanks it really helped
Thank youuuuuuuuuu you are saving my life right nowwwwwwww
BEST VIDEO EVER
Thanks!
I wanna ask a question. When we measure potential difference, the positive end of battery is connected to positive end of voltmeter, in measuremnet of current, positive of battery is connected to positive of ammeter but in emf it is opposite? Can u plz explain this. shouldn't positive ends be connected to negative for flow of charge???
Am always watching ti's before schl
Thank you so so much
I would really love if you could explain the development of higher and lower potentials inside the source of emf. Thank u and really helpful explanation.
your way of explanation is unique
very nice video
amazing vids for revision! keep it up dude
Amazing
I needed this.
Can we say that the electromotive force transfers other forms of energy to electrical or do we have to state that it's chemical
very well.explained
👍👍👍👍👍
Very very nice electrical physics was never this much interesting
Thank you 🙏
Awesome video. Thanks a lot, your explanations are very clear ^.^
Where I live, it's very hard to find a good a level physics teacher. People like u make our life easier. Saying thank you is not enough to appreciate ur efforts to teach us. 💙💙💙💙💙💙💙💙💙
very good explanation! keep going...
Thanks
Wouldn't it be more correct to say that the electrical energy becomes vibrational kinetic energy in the atoms, which causes it to radiate thermal energy and light?
You are talking about "charged particles" movement and "current flow", but as i know the only particles that move are electrons making the current flow. So what are these "charged particles" ?
Electrons
If electromotive force by definition is the rate of energy transferred from chemical to electrical energy per unit charge. Why is it not considered in terms of being a force?
yes i got that...thanks bro
Thank you sir for the video! I was thinking that the electromotive force was the force necessary to push the electrons in the circuit, but I wonder now how the electrons can keep moving after releasing all the energy to the bulb (in this example). I don't understand.
Electrons aren't moved by energy they move because they are attracted to the positive terminal of each component in the circuit. This is current - the flow of charge carriers from one terminal to another of opposite charge.
does it mean that if we connected a voltmeter to a closed circuit with no electrical appliance connected, it will show zero?
Yes
thanks
Thank you sir
Respect from india, bombay.
Thanks sir 🙏
Very interesting
I do Leaving Cert Physics in Ireland and this is similar to what we learn found it hard to grasp but it’s way easier now thanks!!
can u say why the value of emf and pd are different in this interpretation.?
it was an awesome video but can some one explain at what happens at the atomic level ? i mean does electrons get excited or something?
SIR, As per definition current is flow of charge that means positive and negative charges, but only protons carry positive charge but protons are bound in nucleus Then how they can move?
I think the whole nucleus move
It's a convention, thanks to an accident of history. Benjamin Franklin took a guess without all the information, arbitrarily assigned the signs of charges, got it wrong, and we just never bothered to correct it, because there is a huge body of knowledge we already have, that uses the convention of positive charges flowing.
In any circuit built from metal conductors, it is the electrons that flow. The nuclei are fixed in place, in the rigid lattice of atoms. Only the electrons flow, and they flow in the opposite direction from the direction we conventionally assign as the direction of conventional current. It would create the same field effects as if it were positive charges flowing in this direction, instead of negative charges flowing in the opposite direction.
very good
How is that , you say emf and pd is energy , while we measure them in Volts
Mate, thankyou
Thanks abut 🔥🔥🔥🔥🔥
Bro I want some help in solving past paper qurations could you make some videos explaining how to solve questions offered by Cambridge
Best loved it
Current is the flow of charge per second, but what is charge? I mean i know it's Q= IT, but what is this charge? and If current is the flow of charge then what causes the current i mean what is that thing that carries the charge?
are the charge carries some actual particle that carries the charge?
Onim Dip Charge is a property that some particles have, just like most particles have a property called mass.
Sir, why we say that electron must be in parrell in voltmeter to measure it ,why not in series or what will happen if in series ?
An ideal voltmeter acts as an infinite resistance (you'll see it called impedance on datasheets, since there is a lot more to it than simple resistance). That means, no current flows through it, and you measure the voltage drop across it, without drawing current away from the circuit. If you put a voltmeter in series with a circuit you are measuring, you will end up blocking the flow of current, so that you end up measuring what is known as the open circuit voltage. That may be what you are trying to measure in some cases, but when it isn't, you won't accurately measure the voltage across just one resistance.
The opposite is the case for in-line ammeters. An ideal in-line ammeter acts as an infinitesimal resistance, which short circuits the path between the probes. You have to put the ammeter in series with the load you are measuring, so that there is negligible voltage drop across the ammeter. If you put an ammeter in parallel with a circuit, you will subject it to a much greater voltage drop than it can handle, which will subject the ammeter to way too much power dissipation in it, that could damage the device. Hopefully, it is built with fuses that blow before catastrophic failure happens.
You can also have clamp-on ammeters, that instead measure the magnetic field surrounding a circuit, rather than sending circuit directly through the meter, which is the kind I prefer. This way, you don't need any electrical contact between the circuit you are measuring, and you don't have the unintentional mistake of too much voltage applied to the ammeter circuitry.
Your channel ad came up before this video 😂
really helpful
+KeeegoHD Thanks
nice wow!!!!!!!!!!!!!!!!!!
dies from peak physics
I knew playing with legos as a kid would pay off
the yellow things carried are electrons or shall we say electricity?
They represent the energy per unit charge.
Does this mean that if there is no component then there is no PD? Only EMF?
Yes and no. If there is an open circuit there, then the potential difference would equal the EMF. Both would still be present, they would just equal each other. I know this concept as open circuit voltage.
If you short-circuit the battery, all of the EMF will drop across its internal resistance, which could damage the battery. The terminal potential difference would be zero, as a result of doing this.
the almighty lego master
love it