A Level Physics Revision: All of Electromagnetism (in 38 minutes)
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- čas přidán 18. 06. 2024
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I hope this video is helpful! : ) All of Electromagnetism in under 40 minutes.
All of my revision videos: • A Level Physics Revisi...
Lenz's Law detailed video: • A Level Physics: Lenz'...
Chapters:
00:00 Intro
00:29 Magnetic Field Lines
02:50 Magnetic Field around a current carrying wire
04:10 Right Hand Grip Rule
07:04 Magnetic Field around a solenoid
08:03 Force on a wire in a field, F=BIL
11:33 Fleming's Left Hand Rule
13:34 Charged particles in a magnetic field
15:50 Derivation of F=qVB
17:35 Magnetic Flux
23:08 Base units of magnetic flux density
25:50 Faraday's Law and Lenz's Law
30:08 The AC Generator
33:37 Transformers
This video is useful for all examboards including OCR A Level Physics, AQA A level Physics, Edexcel A Level Physics, CIE Cambridge International A Level Physics 9702 syllabus, Eduqas etc.
Thank you for helping me get an A in OCR A physics last year in 2023! I was predicted a B but your videos helped a lot in me obtaining a grade A. After all the hard work I’ve also successfully got an unconditional offer to study medicine this year! Thanks again
Wow thank you so much for the comment and for the super thanks. I really appreciate it and comments such as these genuinely make my day. Congrats on securing one of the most competitive university places!! I hope you have an amazing time studying and a prosperous career doing such an important and vital job. Well done!!
W
I wish the best of luck to the people, including myself, that are learning the content just before the exam.
Good luck! Drop a comment, if something doesn't make sense!
good luck man
ong bro good luck to you
Big exam tmr!!! Thank u for this ❤️❤️
this man carries my physics grades. your videos are a great revision source. thank you :)
my pleasure! Thanks a lot for the comments and good luck on any exams!
@@zhelyo_physics thank you so much :))
also i have a question regarding transformers. is the emf induced in the secondary coil alternating voltage or no?
yep alternating p.d., the magnetic flux around the secondary coil is changing and that enduces a changing e.m.f.
@@zhelyo_physics thank you for the help.
also sorry i have another question, how would i answer this spec point? im a bit lost
"understand the factors affecting the e.m.f. induced in a coil when there is a
change of current in another coil linked with this coil"
@@justaracoonchillinginatoilet69 that's basically just a transformer and it involves: 1) the rate of change of flux in the primary coil which affects the secondary coil 2) the number of turns ratio described in the equation for transformers in this video. Occasionally they might put a trick question like what would you see if you ran a DC current through the primary coil - a short pulse of current followed by zero current (the short bursts is due to the change on primary from 0 to some DC current and then change again back to 0 )
FBI is the best way to remember Fleming's left hand rule. F = force (thumb) B = mangetic field (index finger) I = current (middle finger)
that's so good! Thanks, never heard of this!
So grateful for this , thank you sir
❤ thanks.
ahahaha damn thats much easier. I've been literally just using ForceField Current, and remembering because it sounds like something out of starwars ahahaha
FBI open up
mocks coming up, this is very handy :)
Good to hear! Good luck on the mocks!
revising for my board exams right now, although this is for OCR, it is immensely helpful for CIE as well, thank you so much!
Anytime! Glad to hear, the core content in most exam board is very similar. Good luck with revision!
@@zhelyo_physics Thank you sir!
how did it go
What a lecture! Hats off. Helped me real good.
Thanks a lot! Glad it helped!
You should definitely do a video on Hall Voltage, as I see that it is missing. These videos are amazing!
Thank you so much bro. I have A level physics exam today , paper 2, and your video helped me a lot to understand electromagnetism. Lots of love for you bro❤️
same, good luck my guy
How was the paper??
@@Subscribe-HelloUK guess well never know
Best lecture on electromagnetism. Keep up the good work Sir✌✌
Thank you!
I hate magnetism; praying to god that there isn’t a 6 marker on magnetism in OCR P2 or P3
You are insane, helping me finish my a level physics faster! Cheers boss
Anytime!
20:32 I’m pretty sure the diagram next to it on the right is the one where the field line is parallel to the area sir!
excellent question, parallel in the context of the angle shown is parallel to the normal of the area, not the area itself. It's a tricky point. Hope this helps!
Thank you so much for the amazing video!
anytime! thanks a lot for the comment!
lovely stuff thank you sir, actually quite similar to AQA spec as well !
Anytime! Physics is physics : )
My favourites channel for a level physics. well explained
Thank you! Much appreciated!
Thank you for this great resource!
Anytime! Thanks for the comment!
Fantastic Video, Thank you!!
Glad it is useful! Thanks! : )
Wow wow wow ,I am amazed ...
You did an incredible work here ...now I can finally understand magnetism🎉 .
God bless you sir ,continue with the good job 🎉🎉
thank you so much for such a kind comment! So glad this is helpful!
Thank you very much! You have once again helped me improve my physics grade!
anytime! very glad this is useful!
Thanks so much, this helps a lot!
Anytime! Glad to hear!
Best video on the subject I've watched
thank you so much for the comment! Much appreciated!
best channel ive come across since you cover the same board and teach brilliantly, thank you very much. lets not forget the drawings too lol.
Thanks a lot! Really glad to hear this : ) Good luck in revision!
Yoo really neat lecture. Good job
Thanks a lot! : )
POV it’s 3 hours before the exam
my dude it always is
I love it for simplifying it that way thanks
anytime! thanks for the comment!
Outstanding lecture 👍👍👍
Thanks a lot!
Your Videos are just soo good
Thanks a lot! Much appreciated!
Is this called 40 minute magic??? Thank you sooo much sir God bless you. And pls pls pls keep uploading more videos
Thank you so much for the kind comment and glad this is useful!
Really Helpfull💯👍
Glad to hear! : )
Best A Level Physics channel
thanks a lot! Much appreciated!
final is tomorrow, thank god for this video
Good luck!
I religiously recommend this youtube channel to my friends lol, no other channel compares to the understanding I gain from you bro
Thank you so much! I really really appreciate this! Deep understanding of physics is precisely the goal of this channel. Thanks!
Great video thanks!! Would it be possible to do a video on the possible experiments for elctromagnetism please? Your materials video was very helpful.
Great suggestion! I am working on it, however just to mention that the possibilities with electromagnetism are almost endless, but hopefully it will still be helpful in terms of a general direction.
@@zhelyo_physics Yes it will be helpful! Thanks
Sir, thanks a lot. Your videos are helping me a lot. I am revising all the syllabus of physics with the help of your videos which is my life savior.
Can you please upload a revision video on Alternating Current (AC) it will be very helpful for me
Thanks 😃😄
Same here,i really found this topic complicating but thanks to this 👍 unique teacher.
@@wofaiibor3353 Thanks a lot!
Thank you!
You're welcome!
Nice one dude
No Problem
Hello sir, did you make a video on the graphs that are in EM induction B VS T graphs, the ones with the weird shapes, sometimes rectangle etc
03:53, shouldnt the filed lines on the fiest wire be going anticlockwise?
Sir could you please do a video going through electromagnetic revision exam questions these videos are so helpful !!
Hi! Check out the community post I have just done, I have recorded virtually all recent questions and summarised them in links to the past paper videos, hope this is useful!
@@zhelyo_physics omg thank you so much your video helped me understand the topic so much !!
Anytime! Glad to hear!
for 33:25 , if we have to find the emf, would we have to draw a tangent at that point, and then find the gradient of the tangent?
yh
thankyou soo much
Anytime! Thanks for the comment!
For the magnetic field around a solenoid, how do you know for sure which end is the North pole? Is it the right hand grip rule, because when I try to use that my direction for the magnetic field changes depending on which end I look at (if the current is going up or down).
Hi, I have covered this here: czcams.com/video/GTyJcSzDXzY/video.html
7:28
Using Right hand grip rule on the diagram, wouldn't the North-pole mentioned in the video be South-pole instead and vv?
According to the fact that the for a cross sectional area of a solenoid, if the current is flowing anti-clockwise, it is North end of the pole and if it is flowing clockwise, it's the South-pole, the diagram is again reversed.
Excellent question. The field is definitely correct. Some further drawings can be found here: hyperphysics.phy-astr.gsu.edu/hbase/magnetic/solenoid.html Best to think of the field of a single ring, which is also explained here:
hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html Hope this helps!
@@zhelyo_physics hmmm. As the coil is drawn in 2d, I feel this is one of those cases where you can't tell the whether an object is closer to you or not.
Taking the side that I first viewed closer to me as the farther one is definitely helping.
@@zhelyo_physics Nonetheless, great video. Helping me through my OCR revision.
5:31 ruler jumpscared me lol
So, if I understood BILSinTheta correctly, then the electrons move in a spiral in the direction of the current flow?
Life saver
Thank you for the comment!
in the edexcel book they used Φ=BAsinθ instead of cos. so i guess the graph here 32:15 would be different too, since sin90=1?
Yep! Correct, I teach OCR and the angle is defined in terms of the normal. If they used the sin graph it would be defined in terms of the surface which makes total sense. The graphs would look the same, just shifted by 90 degrees. Thanks for your comment, very useful to know how various exam boards define quantities.
i saw very good thing on you. this vid initiate some ppls like me
Hi!! Thank you!! It has helped so much!! Have you got anywhere I can get the notes?
anytime! Sorry only the videos are available, I do encourage students though to use them to make their own notes.
@@zhelyo_physics okay thank you!!!
Excellent drawing Z. I appreciate the video as always, helping me prepare for next months exam....
Thanks!! Glad it's helpful, good luck on the exam!
hi sir, what do we need to know for an AC generator (OCR A)?
do we need to know the brushes and slip rings? or just that the rotation of the coil causes change in flux therefore emf and current induced?
we need to understand the principle of operation, in terms of basics of electromagnetism and changing of magnetic flux linkage. Brushes, slip rings are not on the specification. If something like that appears it may be part of a diagram or context set within the question. Hope this helps!
@@zhelyo_physics great thank you sir
thanks
Anytime!
tysm
Anytime!
7:07 ....but wouldn't the magnetic field be travelling from A to B in the front and B to A in the back , since they have to run a full circle. So why did we assume only the first case to be the answer ?
Just a matter of reference point. Looking at the diagram as it is drawn in the picture we can describe the field as going out of the page/screen at A and into the page at B . An alternative way to think about it outside of the diagram shown is to imagine a wire with the current going into the page, the field will then be circular with a clockwise direction. Hope this helps!
Excellent question by the way!
23:00 wouldnt you need to do a bit of trig to find the area
No, just 90-55 to get angle subtended by normal, then times area by cos angle
Think of the cost part as working out the fraction of the area that is 'in the right direction'
Next step: practice questions walkthrough: czcams.com/video/N8jUe1DPuNw/video.html Hope this is useful! : )
Hi again, at 3:10 'current' into the screen is a cross, but at 13:51 a cross is the 'magnetic field' into the screen, just wanted to clarify why that is different?
excellent question. So the cross is the direction only and not the quantity that is in question. Think of it as an arrow that could signify things like current, force, magnetic field etc. The only difference from an arrow drawn on the screen is that this arrow is into it. Hope this helps!
Exam is in 9 hours and 25 minutes, we are getting in uni!!!💪💪💪💪
appreciate your drawing
haha thanks! It took a while! Difficult to teach a 3D concept on a 2d surface.
5:43, please was that Fleming's right hand rule,am confused
yes, correct!
which software is this
Microsoft Whiteboard
Why haven't you included the hall effect and the current balance method?
Hello! They are not part of all exam board specs.
Is this video alone enough for the exams?(With ofcourse Past Paper practice)
I would also have a look at any teacher notes and the syllabus to make sure you have covered everything. I also have a video on electromagnetism experiments I would add to this. Good luck!
What kind of practical skills could they assess to do with Electromagnetism?
million dollar question! I will make a video about it but the best thing to do would be to know the spec inside out, then, solve all the available problems. In short things could appear include - any situation in which there is a changing flux, creating an emf, or lots of things including oscilloscopes or graphs and gradients.
4:10 damn good drawing tbf 😭😭
ahaha thank you!
Another way I use to remember 11:33 Fleming's Left Hand Rule is "FBI"
ohh just saw someone else commented this already haha
Thanks for mentioning it! Before the comments I had somehow never heard of it before : )
What do they mean when they say the core of a Transformer is laminated?
The core links the primary and secondary coil. Normally it's a piece or iron, however often you get Eddie currents within it and laminating the core (usually with a high resistance materials) reduces these currents and the efficiency . Hope this is helpful!
What's "A level" in your country? I keep seeing this term but does this mean college level or high school? I'm from USA, sorry
Sure, it's very similar to an AP course in Physics in the States, but non-calculus based.
Wow
is Motor effect in the ocr spec?
the spec doesn't call it the motor effect persay but yes the principle is there.
If you were a stock, I'd invest in you rn!
1:15 why is the the North Down and South up while it should be the opposite
The magnetic South Pole is at the geographic North Pole. So the North Pole of a magnet is attracted to the south magnetic Pole and points towards it. Basically they are reversed.
at minute 32.00 why does the normal change ?
so the normal to each side of the surface is almost like a ruler that has been glued vertically to stick out of a surface. As the surface rotates the ruler will change its position. Hope this helps!
30:04 there is no link in description
Hi, it's there you should be able to see it. It's got a heading Lenz's Law Detailed video.
Why do they teach Flemming's Left Hand rule at school? At uni right now all I ever use is the right hand rule for all cross product based stuff including EM. What's so special about Flemming's Left Hand rule?
I agree. Most likely historical reasons. From uni I just tended to remember the cross product rule which together with some intuition about vectors is very powerful.
is this a part of as level?
Nope. A Level only.
For what exam board is this?
Applicable to all. Always check with your spec for minor differences.
@@zhelyo_physics alright thankyou
anytime!
Is all of this a part of 2023 syllabus please tell me
Which exam board exactly? I recommend googling the syllabus and using it as a check list. One of the best ways to revise. Whichever exam board it is, chances are it would be extremely similar.
@@zhelyo_physics A-level Cambridge
www.cambridgeinternational.org/Images/554625-2022-2024-syllabus.pdf syllabus is right here, it is virtually identical up to AC currents : ) Good luck revising!
I love transformers
It's a pretty good film : )
@ZPhysics this channel is a good place to pun😭
Who's here cramming the day before the exam?
Good luck!!
I write my physics exam today ;-;
Good luck! You've got this!
@@zhelyo_physics Thank you!
so, who else is here preparing for tomorrows exams
Father( force)mother *magnetic field )child (current )is better
+++False! There are no 'field lines. Stop confusing lay ppl including many professional. What 'field lines' are, are 'magnetic equipotential lines' which is another way of saying 'lines of same strength within the field' or 'lines of same energy density within the field' [akin to isobars. And, since there is no 'flux' [as commonly defined' 'flux density is another misnomer'
I've just demonstrated the gross misunderstanding academia has of physical sciences.
What are the Properties of Magnetic Field Lines
The tangent drawn to the magnetic field lines gives the direction of the magnetic field.
The closeness or density of the field lines is directly proportional to the strength of the field.
Magnetic field lines appear to emerge or start from the north pole and merge or terminate at the south pole.
Inside the magnet, the direction of the magnetic field lines is from the south pole to the north pole.
Magnetic field lines never intersect with each other.
Magnetic field lines form a closed-loop.
Field lines have both direction and magnitude at any point on the field. Therefore, magnetic field lines are represented by a vector.
They denote the direction of the magnetic field.
The magnetic field is stronger at the poles because the field lines are denser near the poles.
Obviously mostly wrong.
You are so full of yourself [self-important]!
===
I'm formulating the PARALLAX ELECTRIC THEORY which dispenses with the idea of magnetism which is but a historical anachronism, a misnomer, for matter having structured/organized polarity [positive and negative charge] via matrix/lattice/crystal/geometric-molecule/alloy units [depending on it's construction]. The concept of mag lines of force is another antiquated anachronism.
In support of the aforementioned, all electric and magnetic fields are measured using the same equipment - magnets, coils, etc. ++++++So You Think You Know Physics. The Big Misconception About Electricity [Veritasium] - czcams.com/video/bHIhgxav9LY/video.html
bad