A Level Physics Revision All of Electrical Circuits (in 53 minutes)

[@kingzmash9124]

Thank you for this, you provide SO much value with your hard work. I hope you take over Physics A level on YT ;)

[@zhelyo_physics]

thank you so much for the kind comment! I am glad my work is useful, that's the best prize! : )

[@carmenalonso5623]

I've never understood electricity properly until now, it finally clicked!! Thank you so much!

[@zhelyo_physics]

amazing, thanks a lot for your comment, much appreciated!

[@akirawan7708]

Been really struggling with electricity. This video has broken it down so well for me and I feel my knowledge gaps have been filled.

[@zhelyo_physics]

thanks a lot! much appreciated!

[@whatchickens_]

almost all my classmates use your resources, probably the best physics revision channel for A levels on youtube, many thanks

[@zhelyo_physics]

wohoo, honestly, so rewarding to hear! thank you so much and good luck revising!

[@maiamarcou3161]

your videos are incredibly helpful, it feels like im really understanding this for the first time!! thank you so much for all your hard work :)

[@zhelyo_physics]

thank you so much for the comment!

[@batuhantancuay]

Electricity finally clicked thanks to you, thank u so much 🙏

[@Rayyjan]

Thank you so much man now i feel way better for my mock tomorrow :D

[@zhelyo_physics]

Anytime! Good luck!

[@ayoadeneye4721]

This was really really good, thank you very much sir, your physics videos have been so useful :)

[@zhelyo_physics]

thanks a lot! This is much appreciated!

[@TKgreatest]

By FAR the best teacher, keep it up man!

[@zhelyo_physics]

Thank you so much! Very much appreciated!

[@azmanfaruqui2861]

Love the explanation and the vid...I left tution because ur explanation is enough...thank u soooooo much sir..ur a lifesaver

[@zhelyo_physics]

Wow thank you so much for the comment!

[@puddleduck1405]

THANK YOUUU. haha im watching this a few hours before my y12 exams

[@zhelyo_physics]

Good luck! You've got this!

[@puddleduck1405]

Thanks! It was quite hard they took the questions from past IB papers instead of A level but I’m hoping the grade boundaries will be low since everyone found it hard :)

[@dnishal]

how are you finding it now? and do you have any tips you could give someone like me? (i started yr 12 this year)

[@JettixX]

Same

[@theaizere]

@@dnishalstart revising for the exams now, do it everyday, even if 30 minutes, active recall all that. read ahead, practise- but only after blurting for example and solidifying knowledge, explain the concepts to whoever will listen, identify gaps generic but effective, good luck 👍

[@chrislin-cb8oe]

Big Fan from China, u really help a Chinese international student a lot, thank u so much

[@zhelyo_physics]

thank you so much for your comment! Much appreciated!

[@miasruonanlia]

I was hardly able to understand physics in general especially circuits however to prepare for my resit paper a few days ago, i used this video and circuits became so easy for me. I am actually confident in answering questions now! Thank you so much for all your a level videos, helped me prepare so well :) I'm finally able to understand the physics concepts and i have high hopes for the unit 1 + 2 paper i just gave 👍

[@zhelyo_physics]

Wow amazing! Thank you so much for this! Genuienly, comments such as these make my day!!

[@cheyannramma5113]

43:35 its 540 ohm not volt. Great video keep it up

[@g1nnr]

This was was my worst topic, this video helped so much thank you thank you thank you!!

[@zhelyo_physics]

Glad it helped! Thank you for the comment!

[@QuaternionPhysics1]

Hi, is it possible to make an extra video on how open/closed switches affect the circuit and what happens? I understand them and make logical sense, but I tend to get some questions involving them wrong, and want to understand what actually happens? Thanks!

[@zhelyo_physics]

Sure! I'll have a look. Could you give me a specific question?

[@harshiniirvin9143]

@@zhelyo_physics yes please! I find this particular type of question brain racking!! Could you make a video on solving a few examples? thanks and really find your videos useful

[@anonymous99923]

@@harshiniirvin9143 he asked for a specific question you noob smh

[@m4rzb4rz-qq3yq]

Great video! I'm wondering though, at 21:25 why do we do 12-9.3? I dont know how that finds the voltage

[@amenmolla7203]

The voltage across a closed loop is 12 (Kirchoff's 2nd law) and we calculated 9.3 volts which is on the same loop so since it should add up to 12, we subtract 9.3 from 12 to find the remaining available voltage

[@m4rzb4rz-qq3yq]

​@@amenmolla7203Thanks so much, appreciate it

[@m4rzb4rz-qq3yq]

Ohhhh i know what I did wrong, I thought the 12 came from the resistor for some reason 😂

[@SuperCoolBrothers]

Hello; Thank you for these videos, they are much appreciated, I do have a few queries however. Firstly, how much of the content of the OCR specification are covered in your videos? And secondly; On your previous video of this module "Current and Charge", you stated that in an electrolyte solution, positive ions move to the anode and the negative ions go to the cathode. Would it be possible if you could explain what you meant by this? My resources regarding the OCR material stated that the positive ions go to the negative terminal and the negative go to the positive- Many thanks and my apologies for the hassle.

[@zhelyo_physics]

Anytime! So my videos cover 100% of the spec, the videos from my revision playlist. Regarding the electrolyte the wording on those questions can be tricky. Check out this question from OCR (old spec): Question 2 from this paper: www.physicsandmathstutor.com/pdf-pages/?pdf=https%3A%2F%2Fpmt.physicsandmathstutor.com%2Fdownload%2FPhysics%2FA-level%2FPast-Papers%2FOCR-Old%2FUnit-2%2FJanuary%25202011%2520QP%2520-%2520Unit%25202%2520OCR%2520Physics%2520A-level.pdf Mark Scheme is here: www.physicsandmathstutor.com/pdf-pages/?pdf=https%3A%2F%2Fpmt.physicsandmathstutor.com%2Fdownload%2FPhysics%2FA-level%2FPast-Papers%2FOCR-Old%2FUnit-2%2FJanuary%25202011%2520MS%2520-%2520Unit%25202%2520OCR%2520Physics%2520A-level.pdf Hope this helps!

[@SuperCoolBrothers]

@@zhelyo_physics Thank you kindly. Much appreciated. One more query, apologies: Do specific conditions of the electrolytic system (like polarity electrolyte composition, potential difference. eg.) and the electric field established by the applied potential alter whether or not the positive ions move to the positive or negative terminal in an electrolyte? Or is it a constant that the positive ions move to the positive terminal? My material says "The positive ions move towards the cathode, accepting an electron, and the negative ions move towards the anode, donating an electron to flow in the metal part of the circuit", and I admit I'm a bit confused- I apologise for my confusion. Many thanks. :)

[@ozone9942]

Thank you for these! I have one question, which way should the LED be connected to a cell or a power supply, just because some past papers are slightly confusing me about polarity and orientation of the LED relative to the supply.

[@zhelyo_physics]

anytime! So the triangle of the LED should be pointing from the positive terminal (the larger one) to negative (the smaller one)

[@basic-ly]

I was confused at 30:40 because I counted resistor a and b to be parallel to c and d and thought that if resistors a and b are getting 24V in total from emf, then since c and d are parallel they will also have 24V. My mistake was including Resistor A as being included in parallel branch!

[@azmanfaruqui2861]

For parallel I prefer using the formula R¹xR²/R¹+R²..it's the extra enhanced of the formula in the video

[@zhelyo_physics]

Excellent!

[@ghostty6712]

in 30:36 how did you get that the voltage of the resistor D is 14V ? Would it not be 16V as the total emf is the sum of potential differences in one closed loop so if we look at the first closed loop the total is 24V and this would also be the same for the second closed loop so the voltage of D would be 24 - 8 = 16V right ?

[@zhelyo_physics]

excellent question, you have to consider the 2 V resistor as part of the loop as well, then it adds up to 24. I hope this helps!

[@ghostty6712]

@@zhelyo_physics omg Im blind sometimes. Thank you soo much

[@prith7900]

thank you for this video, im in CAIE, and i just wanted to know when taking values that arent the answer, do we have to still take it in 2 s.f?

[@zhelyo_physics]

normally it's good practice to round once right at the end. Hope this helps!

[@shadowdragon1892]

I'm enjoying this playlist so far, do you know if there are any topics missing for AS? Or does this playlist cover basically everything for AS physics. I do OCR A too. Thanks!!

[@zhelyo_physics]

for OCR A it would cover virtually all topics, just in case it might be worth to have the specification at hand and use it as a checklist.

[@NOH-il4js]

hello, very good video. For circuit analysis 2nd example , I understand why Vd= 14 but I also thought that C and D were part of one closed loop, and since Vc = 8v i thought Vd would be would be 24 - 8 = 16v.

[@zhelyo_physics]

resistor A is also part of the closed loop. Hope this helps!

[@NOH-il4js]

@@zhelyo_physicsYes that makes sense I rewatched I and didn’t realise you explained it after . Thanks.

[@sajimio]

hi! thank you so much for the video it really helps but i have a question, why in the example 2 we have 8V and 14V on the resistors on the second loop? why is it not 8V and 16V? should not that be equal to 24V, why 22?

[@urdudebatesabdulmoeez]

physics best teacher

[@zhelyo_physics]

thank you so much!

[@greenjars_]

Great video! One question, at around 36:45 you mention that in the experiment you measure terminal pd. Does the voltmeter not measure EMF as the two points are connected in parallel across the cell and internal resistance portion? Or am I getting mixed up with my definition of terminal pd?

[@fungamingtv1111]

Emf is the voltage before it leaves the cell, while pd of the cell is the voltage leaving the cell I believe. So emf is greater than pd of terminal. Pd is what you would measure with the voltmeter, while emf is the pd you would have if there was no internal resistance.(unless I'm mistaken lmao)

[@jamiecroll]

At the end when you do he themistor and LDR examples, if you know that the resistance of the thermistor goes down, can you just straight away say that the voltage goes down using the potential divider equation in the formula book? Since the ratio of R2 and R1 + R2 decreased. Or do you have to go through each of those steps you stated?

[@zhelyo_physics]

you can justify it with a formula too. Hope this helps!

[@ocelot9643]

Why does the total resistance decrease with the thermistor but increase with the LDR if the resistance to light intensity/ temperature relationship is the same?

[@zhelyo_physics]

Sorry which part of the video are you referring to?

[@VirajMokashi-li6zs]

@@zhelyo_physics I might be wrong but at the very end of the video when talking about the thermistor example you wrote LDR instead of thermistor. Thanks for making these videos tho :)

[@zc6552]

Amazing videos thanks a lot

[@zhelyo_physics]

Anytime, thank you for the comment!

[@rrailz6510]

Why at 21:59 are both the resistors in parallel equal to 2.7V? Isn’t the total potential difference in parallel shared and not the same for each resistor? Shouldn’t 2.7V=V12+V36 ?

[@zhelyo_physics]

Nope shared in series, in parallel we use Kirchhoff's 2nd Law that the sum of the emfs=sum of the p.d.s in a loop. Hope this helps!

[@RaidenTheTomb]

Hi Sir thanks for the detailed explanation...I understood it much better than in school...do these videos cover the CIE AS level syllabus also? Are both the syllabi the same (OCR and CIE)?

[@zhelyo_physics]

yes, they are extremely similar, I recommend using the syllabus as a checklist, going through the videos and then supplementing with lots of problems. Good luck!

[@RaidenTheTomb]

oh ok thanks sir@@zhelyo_physics

[@syakirah2640]

thank you for the video ! it was very helpful :D

[@zhelyo_physics]

Anytime! Thanks for the comment!

[@mc_dzzy4625]

Great and beneficial video, however at 23:57 theres a rounding error that contradicts kirchoffs 1st law, the I-36 should be 0.7. Nevertheless i appreciate your great work.

[@zhelyo_physics]

ah yes! I guess in Physics that's why we always take the absolute uncertainty to be +- 1 of the the final digit. Thanks for mentioning and great feedback!

[@TazwarMustafa]

Bro you are a lifesaver

[@zhelyo_physics]

thanks a lot for the kind comment!

[@luddy20]

your videos are the best I haven't been able to understand electricity since yr 12, what's the definition of a potential divider and can I use its equation in aqa?

[@Zion2-zq1bp]

u y13 too? exams in a a week or two?

[@zhelyo_physics]

thank you so much! You would rarely get asked to define a potential divider, however it is a circuit that divides voltages between components. The equations can then be applied. Hope this helps!

[@lesnowguade8208]

Hi, is deriving the equations for combined resistance part of the spec? As in would it be a possible question in the real exam?

[@zhelyo_physics]

not really but it can be asked potentially I think as a show question.

[@lesnowguade8208]

@@zhelyo_physics Thank you!

[@notoriouscookie7066]

You’re so goated ❤️❤️❤️❤️❤️❤️

[@zhelyo_physics]

thank you for the comment!

[@maravankarunakaran3894]

reminder for myself - look back at kirchoff's 2nd law example

[@zhelyo_physics]

good luck!

[@toriiramlall6638]

Thank you sir!

[@zhelyo_physics]

Anytime! Glad this is useful!

[@davidcampbell3579]

At 45:36 you wrote 540V, shouldn't it be 540 Ohms? Otherwise thanks for the wonderful revision video!

[@zhelyo_physics]

yep, should be Ohms, thanks for spotting the typo and the kind comment!

[@jonathoncornly7779]

Could I ask if this video covers the same content as the other separate electricity videos in the 'all of' playlist? Would watching this one be enough or is there new content in those ones?

[@zhelyo_physics]

the content is sometimes a bit more in depth however all relevant bits to the spec I have included in the All of video. For convenience : )

[@tayyibjamil8573]

Will your video on all of potential dividers be enough for my Aqa AS physics for electricity or do I need to cover this as well?

[@zhelyo_physics]

you want to cover this one too.

[@onestartrailer5741]

would you mind making a video where you go through kirchoffs second law questions?

[@zhelyo_physics]

sure! Here is a difficult one here: kzbin.info/www/bejne/q2Wtm3tpa7F6mdE I will make a video on this as a topic though. Thanks for the idea!

[@sptparts5893]

at 45:43 is it 540 ohms rather than voltage?

[@zhelyo_physics]

correct! Thanks for spotting this!

[@teacupcakes2739]

omg, i tried the 25:40 question by myself before watching and I didn't realize the top component had a decimal point in between voltage 🤦🤦

[@qiangtianxue8444]

just asking isn't drift velocity part of ectrical Circuits?

[@zhelyo_physics]

Hi I've included in the Charge and Current video here: kzbin.info/www/bejne/gqPRdXymZbCcpqssi=gQja1mqDw7TYmNV8 Please also note there is also this electricity video here too: kzbin.info/www/bejne/j3m3maKKpNB7e9Usi=U0uv-IRa72GVR9Md

[@qiangtianxue8444]

@@zhelyo_physics thank you so much

[@zhelyo_physics]

anytime!

[@qiangtianxue8444]

@@zhelyo_physics Hello, I would like to ask is semiconducter in part of the electricity topic?

[@SyedghulameTahaBukhari]

33:40. Shouldn't this be lost energy per unit current?

[@zhelyo_physics]

I have a feeling I have seen the definition as in the video in an old mark scheme. As r=Vlost/I lost volts per unit current seems apropriate as the volts are energy per unit charge. Hope this helps. Excellent question!

[@SyedghulameTahaBukhari]

I meant regarding what you said in the video. You said "lost energy per unit charge". This does seem more correct now when I think about it since voltage is energy/charge. But if we follow the definition which shows on the screen then shouldn't it be energy per unit current? Also, resistance isnt a measure of voltage lost though. The measure of that is voltage itself (since it is the work done by the charge carriers on the resistor and therefore energy lost). The equation for lost volts is Vlost = Ir which equals W/Q because Vlost isnt resistance you wouldn't you use these equations instead of a one for resistance (i.e. r= Vlost/I) Could you answer this please? I dont mean to be rude.

[@zhelyo_physics]

no probs, excellent question - definitely not energy per unit current as this does not have the units of resistance. Resistance is voltage/current and voltage =energy/charge therefore resistance is energy/ (charge x current) Hope this helps!

[@SyedghulameTahaBukhari]

@@zhelyo_physics yes but why are we using the equation in terms of resistance (r=Vlost/I) and not voltage (Vlost=Ir) because if it is "lost volts" then shouldn't we be using the equation in terms of voltage and not resistance?

[@chiki-24434]

THANK YOUUUUUUUUUUUUUUUUU

[@zhelyo_physics]

Anytime!

[@MuhammadUsman-kp6ft]

hey! any video for test cell?

[@zhelyo_physics]

by test cell do you mean this experiment? kzbin.info/www/bejne/d5yqnoF7n7F0las

[@MuhammadUsman-kp6ft]

No in which we use a crocodile clip to determine the emf of a test cell

[@archietaylor5964]

THANK YOU

[@zhelyo_physics]

Anytime! Thanks for the comment!

[@benbeaton5410]

This is really helpful thanks!

[@mohammadallyrujub2841]

45:40 its ohm not volt

[@zhelyo_physics]

Thanks for spotting

[@beaulamvere343]

Thank you

[@zhelyo_physics]

anytime! thanks for the comment!

[@zafirayan3230]

Nice 👍

[@sagormehedi]

sir where is drift velocity

[@zhelyo_physics]

kzbin.info/www/bejne/gqPRdXymZbCcpqssi=jpe0oHpX22GETt50 just here

[@jche6587]

thanks！

[@zhelyo_physics]

anytime! Thanks for the comment!

[@hummusmixedwithapplesauce4889]

What exam board is this from?

[@zhelyo_physics]

Hi! I teach OCR Physics A but I think this section is almost identical across the exam boards.

[@hummusmixedwithapplesauce4889]

@@zhelyo_physics Oh ok. Thanks. Just wanted to use this video for revision but needed to verify it was OCR A

[@butterscotch3728]

superb

[@zhelyo_physics]

Thanks a lot for the comment!

[@cheems3679]

21:37 why did you do 12-9.3

[@zhelyo_physics]

So Kirchoff's 2nd law says that sum of the EMF=sum of the p.d.s i.e. 12=9.3+V , i.e. V = 12 -9.3 (where V is the p.d. on the resistor on the right). Hope this helps!

[@cheems3679]

@@zhelyo_physics thanks haha, watching this again after school mocks , you are the GOAT 🐐

[@passingoutinasec1172]

Can u also provide these notes plz

[@zhelyo_physics]

sorry only the videos are available at the moment, will be creating electricity problems workbooks soon though. Stay tuned!

[@joysulislamjony]

Today at 8am i have as phsyics u2 exam and im going to fail ig😓 now its 4:30am

[@zhelyo_physics]

you won't! Good luck tomorrow! You got this!

[@dnishal]

guess whattttt only 3 chapters left 😁 well acc two from the 13 as imma start Waves 1 today aswell. but my point is in 2 weeks i covered the whole of paper 1 basically. thank you so much zphysics, i honestly have no clue how you do this all for free and you should genuinely put up a donation account.

[@zhelyo_physics]

thank you! Great to hear about your progress, well done, very few left!! : )

[@xavierbard-h6u]

pov : your a day before your exam and havent revised yet'

[@zhelyo_physics]

Good luck in revision!

[@BS-SALEH]

7:06 how is that a series circuit ??

[@zhelyo_physics]

he the circuit is not, the cells however are connected in series as opposed to parallel. Hope this helps!

[@best_mate456]

45:30 you put voltage when supposed to be resistance btw good job otherwise

[@sultanahmed1971]

Thank you

[@zhelyo_physics]

Anytime!