Potential Difference vs. Electromotive Force - A Level Physics
Vložit
- čas přidán 14. 05. 2015
- 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
_____________________________________
MY PHYSICS WEBSITES
Find even more videos organised by exam board and topic at:
GCSE Physics Online
► www.gcsephysicsonline.com
A Level Physics Online
► www.alevelphysicsonline.com
MY CZcams CHANNEL
Your support in watching this video has been invaluable! To contribute towards the free videos on CZcams, make a small donation at:
► www.paypal.me/physicsonline
FOLLOW ME
► czcams.com/users/physicsonline...
► / physicsonline
► / gcseandalevelphysicson...
#electricity #alevelphysics #physicsonline
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
your explanation are clear and so helpful; thank you so much I don't know what would i have done without them.
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 :)
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...
Absolutely wonderful video. Easy to understand analogy. Clears my concept very much. Thank you!
Very nice explanation. Thanks for the video!!
This was great. Thank you so much!
These videos are superb, keep them coming!
Your videos are awesome and very helpful, keep up the good work👌
Brilliant explanation! Thanks!
This is so good! Thank you.
This explanation is absolutely brilliant !
Thank you so much for this innovative idea.
Well explained. Thank you.
Excellent explanation!!
Wow great vid and explanation. Thanks
i was really confused about it and was mixing them up thank you for your effort of explaining
All I could think about the entire video is how similar you sound to Josh from the Sidemen. Great video!
Oh yeah
amazing vids for revision! keep it up dude
Awesome video. Thanks a lot, your explanations are very clear ^.^
Bro thank u so much great explanation 😍
these videos are absoluetly brilliant
Thank you - there are now over 500!
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!
Thanks mate now i get it, great explanation.
I love you so much for using Legos to help me understand this. Thank you Lewis!
I needed this.
Thankyou for your explanation...after 3day of my heard work finally with the help of your video i have cleared may concept:)
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
very sick my guy
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.
Fantastic videos thank you
good attempt to explain the concept
thanks it really helped
It's sooo cuteee I can't!!! But the explanation was excellent! Thank youuuu
wonderful video
Very good way of visualizing it..thnx dude
Glad you liked it!
thank you this was a great help been stressing for a while and you helped me out !!!!!!!!!!!!
Thank you so so much
Thank youuuuuuuuuu you are saving my life right nowwwwwwww
very well.explained
👍👍👍👍👍
PD is what we were taught as voltage drop back in the dark ages.
Thank you 🙏
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.
thank u so much
thank you
I am 14 and This was so helpful thanks a lot
very good explanation! keep going...
Thanks
Am always watching ti's before schl
Thank you
BEST VIDEO EVER
Thanks!
Amazing
Great videos. Please keep making them.
+ModdersApprentice Thanks - hope they're useful.
Very interesting
Thank you sir
Thanks sir 🙏
yes i got that...thanks bro
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. 💙💙💙💙💙💙💙💙💙
Best loved it
Mate, thankyou
very good
i love your teaching style💞❣️❣️❣️❣️❣️
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.
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' ^^
Very very nice electrical physics was never this much interesting
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?
can u say why the value of emf and pd are different in this interpretation.?
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
love it
really helpful
+KeeegoHD Thanks
Can we say that the electromotive force transfers other forms of energy to electrical or do we have to state that it's chemical
Respect from india, bombay.
Thanks abut 🔥🔥🔥🔥🔥
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???
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
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.
holy shit this helped
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?
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?
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?
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!!
i just love your" little green men"... Keep making videos!!
Your channel ad came up before this video 😂
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.
How is that , you say emf and pd is energy , while we measure them in Volts
dies from peak physics
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.
nice wow!!!!!!!!!!!!!!!!!!
hey sir could u solve some mathematical problems from electricity
this chapter really boggles my mind and confuses me a lot
#IAL #unit2
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
4:30
your way of explanation is unique
very nice video
does it mean that if we connected a voltmeter to a closed circuit with no electrical appliance connected, it will show zero?
Yes
thanks
Just had the biggest click I ever had to understand Potential diffference, while watching this. Thank you so much
Not a problem - it's great when those moments happen and all becomes clear,