Internal Resistance of a Battery, EMF, Cell Terminal Voltage, Physics Problems

This physics video tutorial explains how to calculate the internal resistance of a battery when connected to a load resistor. It explains the difference between the terminal voltage across the resistor and the emf or electromotive force generated by the cell. This video contains examples and practice problem showing how to calculate the terminal voltage and the battery and the internal resistance of the cell. The terminal voltage of a battery decreases when electric current is drawn from the cell. As the current delivered by the battery increases, the terminal voltage decreases.
Electric Current In Circuits:
• Electric Current & Cir...
The Electric Battery:
• The Electric Battery a...
Ohm's Law Problems:
• Ohm's Law Explained - ...
Resistance and Resistivity:
• Resistivity and Resist...
Resistor Color Code:
• Resistor Color Code Ch...
______________________________
Electromotive Force of a Battery:
• Electromotive Force of...
Drift Velocity and Current Density:
• Drift Velocity, Curren...
Potential Difference Between Two Points:
• Potential Difference B...
Alternating Current Vs Direct Current:
• Alternating Current vs...
______________________________
Schematic Diagrams & Symbols:
• Schematic Diagrams & S...
Open, Closed, and Short Circuits:
• Open Circuits, Closed ...
Resistors In Series:
• Resistors In Series - ...
Resistors In Parallel:
• Resistors In Parallel ...
Physics PDF Worksheets:
www.video-tuto...

[@TheOrganicChemistryTutor]

Final Exams and Video Playlists: www.video-tutor.net/

[@sruplal]

For nearly 2 years, this concept has baffled me. Now I totally understand. Big up

[@marissa954]

OMFG U SAVED ME..ALTHOUGH UR VOICE ALWAYS MAKE ME SLEEP..U ARE A REALLY HELPFUL AND GOOD TEACHER..THANK YOU!

[@TheOrganicChemistryTutor]

Thanks

[@ericcartman1168]

@krisda there's this feature on the phone where you can turn up the volume

[@geeksharma6722]

@@ericcartman1168 dude im on a MacBook Pro with headphones and all the volume options on max, I just have a ceiling fan on above me and I still barely can hear what he's saying.

[@Arkalaky2]

You are killin it with this videos. Do you have plans to start magnetic fields anytime soon?

[@tiathathiah9861]

My exam is in like 30 mins 💀💀

[@tiathathiah9861]

Zeyin Mukhanov I ended up getting an A 😂😂

[@jimhalpert9803]

GG

[@gameemdacosta7401]

Fr😂

[@itsawildrk2360]

Lmao feelz

[@shreenidhhi8633]

i have my exam in 11hours :(

[@sapphireblue9209]

OH MY GOSH THANK YOU SO MUCH. NOW I FINALLY UNDERSTAND EVERYTHING THAT I MISSED IN CLASS. YOU EXPLAIN THINGS SO WELL TYSM FOR ALL YOUR VIDEOS AND PLEASE KEEP IT UP. THANKS.

[@vibacourtney-battista6918]

excellent video on this topic, this was the only part of AS physics i was wobbly on before tomorrows exam

[@kyliek.9481]

I fucked up my first paper 😭🔫

[@jimhalpert9803]

@@kyliek.9481 F

[@LifeUnfolded1]

Eventhough I dont take any physic class , but I'm gonna save these video so I can learn it myself this summer time

[@supreetsingh987]

That's awesome 🎉

[@tgkiremttube9097]

thu ha ada

[@arunaprabhu2892]

Very good

[@sahitiputcha]

Thank you so much. It's really helpful. You are a very good teacher...

[@dilaraflor4191]

At 3:10 you used the total resistance to solve for the current but at 8:42 you solved for the current by only using the R of the load resistor should it not be the total (r + R) when solving for the current ?

[@masaemwas5919]

Yeah that part confused me too

[@emacelikovic1675]

i loooveeee physics yayyy i loveee staying up to study because im too anxious to sleep

[@Og_Moose_]

Who else is here in 2020 cause they skipped all their online classes?😂😭

[@Alex-wn8qh]

I was sick for like 3 days and missed so much this man saved me

[@sanjitsaravanan5303]

lmao me

[@lotus_flower2001]

I ended up falling.. turns out the pass rate of the course was 34% so at least im not alone...

[@amitagarwalla8205]

shut up you burglAR

[@lks9988]

2021 and yes

[@user-wz2uf9gf8h]

This can be helpful but its more like an ASMR to me perfect vid to sleep in

[@andyws0108]

Lmfao

[@stevec9669]

Best explanation on this subject on RUclips. Thanks much.

[@SquatSimp]

This helped a ton- thanks man

[@matomekgorane8880]

Excellent explanation ...I really enjoyed your lesson 🤩🤩 am just looking forward for more lessons ☺️☺️

[@ahmetcan-wp2ou]

I can't speak english but, These lessons are so good.

[@nancylei7273]

Such good video. Although it is not very logic, it is great for me to review.

[@ryanirwin652]

V. clear explanation and logical working. Thank you

[@nixs6061]

This video cleared up a lot of things, thank you so much

[@zarrinrazaq3339]

Usefull demo. What software are you using here?

[@TheOrganicChemistryTutor]

I talk about in this video: ruclips.net/video/rBSuMooMYrs/видео.html

[@hovalgames7819]

My final first year exam in about three hours...
Wish me luck

[@rakshagopinath8984]

thnx a gazillion times !!!

[@user-lk4dg8on6c]

I really enjoy your subject only when you add more questions to it

[@peteralkhabout8920]

how we can calculate it from the graph though ?

[@shadowkokufu9178]

Hi, will you do a video on a VI graph and calculating the internal resistance + current + emf by using the graph please?

[@ayshathulthasleema8668]

Ur amazing sir, all your videos r very helpfull

[@joelcharles2063]

I really appreciate this🙏

[@ibrahimaaly4206]

my physics exam tmr :p

[@Xxxcappie23]

Great vid .At the time 3:35 Why do we not multiply by 101 ohms being the total resistance?? Instead you multiplied by the 100 ohms resistor . I may have complicated this by asking plz explain...

[@aleena158]

If I understand your question right, the R=1ohm
R=100 ohm
Is more like part (i) part (ii)
The question can be taken as find internal resistance when external resistance is (a) 1ohm (b) 100 ohm

[@oyeludejomiloju704]

Thank you 🥺

[@adrianmok8557]

I have a question: if I were to find the internal resistance of a battery, should I use a resistor with higher resistance or one with a lower resistance? Thank you.

[@msmventures799]

Did you find the answer yet?

[@kalindakamwale3929]

I have a question it actually comes from the text book titled "success in electronics" 2nd edition In Unit 2 Direct Current subtitle 2.14 problems. No 14 the last problem. It has fig 2.20, and the question says in fig 2.20, V is a high resistance voltmeter.
a) it reads 6V when the switch is open and 4.8V when it is closed. Calculate the e.m.f and internal resistance of the battery battery. Please help.

[@berhanuedea2590]

Thank you so much! it helped me a lot

[@paulna5526]

finally somebody that knows what they're talking about, excellent job, i can't believe the other ah's on youtube that are providing so much misinfo., it is ridiculous.

[@lineekelaleonard4808]

2. Terminal pd across the battery is measured at 6.2 V. The battery consists of 2 cells
connected in parallel. Given that R_total is 3.1Ω and A measures 2 A:
2.1 Determine the emf of the battery.
How can I solve this JG?🤔

[@amazonabera2918]

sir i love ur videos they helped me alot .sir if u have avideo which shows potential difference between two points in the circuit

[@TheOrganicChemistryTutor]

Here it is:
ruclips.net/video/MnpJocNB6mc/видео.html

[@drpriya23]

Why during charging V= e.m.f + Ir??

[@kalindakamwale3929]

The book is by Tom Duncan. Reprinted 2013.

[@geirha75]

Does it really work in "real life"? I mean calculating internal battery resistance 12V car battery the way done in the video?

[@Kryto]

Can you do the same, but a little more practical? In this situation you wanted to calculate and measure internal resistance, and you had the Emf value. But in a real situation you cant relay on the value you get from the producers. Since most batteries wear out with use (at the same time internal resistance increases)
In other words. Calculate Internal resistance with Emf as an unknown value.

[@benjaminbissick2539]

Agree

[@benjaminbissick2539]

Agree ......please to do so

[@fabijanskrobar1750]

Thats a bold statment for someone with anime profile pic

[@averysoular9847]

@@fabijanskrobar1750 dead body reported

[@sakariasakaria6364]

you great keep it up!

[@lilytang5799]

It is very helpful！

[@IvanPavlov007]

Thanks! And what if it's an old battery? What happens to the e.m.f. and the internal resistance as the battery ages and loses its charge?

[@ziadsydek]

First the e.m.f is what is written on battery's by company's and nothing happens to it but
The terminal potential is the actual value of the battery and as time gose it decrease bec of internal resistance of the battery and this is called lost potential
Then emf= t.p + l.p

[@celwinpaulapas1518]

Waw clean explaination. Thanks

[@hibyelol4727]

Is total resistance same as effective resistance?

[@Robsam28]

Very good explanation .

[@ranganathd5954]

you are a very good teacher thanks a lot sir

[@dhyangundu9635]

I like how that guy uses a calc for multiplying 0.11988 and 100

[@hammadsaeed877]

On which app you teach us tell me plz?

[@onyeagoluhenry60]

A circuit consists of a variable resistor R connected in series with an ammeter and a cell. A voltmeter is connected in parallel across the variable resistor R. the cell is of e.m.f E and internal resistance r. For a certain value of R, the voltmeter reads 4V and the ammeter reads 1A. When R is adjusted, the voltmeter reads 2V and the ammeter reads 2.5A. Draw the circuit diagram and calculate the values of E and r. Please help!!

[@bloodevolver2533]

Aren't they in parallel? You said series?

[@ram_pande8039]

Explained well

[@jillaloo5152]

How to find internal resistance given voltage, current and resistance? Electromotive force is not given

[@frogj0]

how to find emf when no current flows?

[@sn4rdnsn]

yea a magnetic fields video would be great

[@NMPVevoOfficial]

What do we do if they didnt give us the internal resistence? Thanks tho

[@epicbaconugget704]

you can also calculate internal resistance without finding current just by doing (1 - 11.9/12) x 50

[@Todaywalnut]

What's the principle you're using?

[@colamentos4738]

EP1C (ocn) where did you find that? :\

[@Iamsushant-n4c]

I am watching this video in my exam 😊 .

[@wilburanderson4565]

Thanks boss

[@francisseun]

Thank you God bless you

[@sultansultan5447]

For your last equation you divided by -12 and your overall result was .42 however to my understanding another way I tried which goes by the rules of transposition if you have 11.9=12-0.238r if you move the r to the other side of the = side and the same with the 11.9 makes it -r=12-0.238-11.9 then change all the signs of positive to negative to both sides making it r=-12+0.238+11.9 and get result of 0.138. either I'm wrong or you are. If there is anyone here who understands this better then me please explain. Thanks

[@blacklyrics049]

dayum, 11.9 = 12 - 0.238r ; here 'r' is multiplied to -0.238, so you can't just simply take only the 'r' to the other side of the equation, you gotta take the whole -0.238r to the left, if you want to, and the equation will be
11.9 + 0.238r = 12, then you can carry out this...

[@anupamapatham1141]

Thanks a bunch🤩

[@buddhabhushanchakre1767]

Two resistor 12 ohm and 6 ohm are connected in parallel and this combination connected in series with 6.25 ohm and battery has internal resistance of 0.25 ohm how to find emf of battery???

[@itstheannas]

Do you not have the current given? Or the total power dissipated? If so, is it an expression you have to fond or a value?

[@rookiemvp2008]

My brain is exploding trying to understand this stuff

[@imaneggagrass5573]

how do i calculate terminal voltage when internal resistance (r) is unknown? :"(

[@sultansultan5447]

Get your voltage difference between your load. With that voltage find the current using ohm's law assuming you know the resistance of the circuit. After you have the current of the circuit and the voltage difference use equation: vr( the voltage difference you measured) = ( the internal resistance of the battery which you don't know)- Current multiplied by the resistance.
You simply get vr to the other side of the = sign to become a -vr and the internal resistance to the other side so the equation would be your internal resistance= - vr - ir. Vr is voltage difference and ir is current multiply by resistance that would give internal voltage.

[@katushadeeva6909]

life saver

[@chateaubunny]

Are u ever going to do a face reveal

[@angeldust_4518]

or for last r=e-v/I same thing just easier for me to solve straight away if remember this

[@masarratfatimarizvi1240]

Gud explanation

[@brayton6683]

I'm writing a test tomorrow ☠☠☠🤧 it's on circuits and electrostatic

[@carlytran711]

wow thank you

[@elijahkamchize5441]

Final touches 😊 exams at 2

[@idk-dr7fo]

tysm i got it 4jan2022 7:28 pm

[@zeusong149]

isn't that parallel?

[@karanaage3946]

🙏 thanks

[@satarupadebsinha3413]

Nicely explained

[@icemoodmage]

Hands down.

[@noorabbass6936]

ادعم الفديو ترجم الى العربي ارجوك

[@UltraTheBeastt]

what are you saying ???

[@gshsenpai6446]

He is proposing to include Arabic captions for the video

[@ashdora7300]

Exams in 30 min😭

[@andrewnicholas2221]

my exam is in 12 hours and im 12 weeks behind 💀

[@omkardixit7320]

Anyone studying this in 10th grade?

[@gshsenpai6446]

Me

[@SkystormX05]

tysm

[@diana0423]

Thanks a lot!!!!!

[@riyajadhav1911]

thank uuu soo mucchh👍👍

[@manishdevadiga7828]

🙏🏼

[@glizzytothetop]

exams in an hour

[@faithonderi263]

Use the question I gave you plz

[@Gurn33y]

im so fucked

[@DIKSHIT_77]

There isn't anything that you don't know.

[@zohabettul7703]

Why your voice make me sleep🙄🙄🙄

[@aayushhh9402]

I didn't liked this teaching... Sorrry

[@ibrahimalotaibi2399]

Thanks for wasting 19 mins of my time for knowing nothing.

[@user-pi8pd9wc5y]

???

[@telseryt8154]

U mean 10 mins