Resistivity and conductivity | Circuits | Physics | Khan Academy

Let's look at the properties of materials that cause a resistor to resist the flow of current. Created by David SantoPietro.
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[@audreyandremington5265]

Mike will be forever remembered as one of the greatest formula memorizers in the history of science class. His name will be preserved in the great records of human history as being included in this khan academy video.

[@hageraliart]

Lol

[@audreyandremington5265]

@@hageraliart awe I'm glad you liked my joke!

[@asissingh1823]

@@audreyandremington5265 Mike is not a joke. You will now be reported to King Mike. Mike is inevitable.

[@audreyandremington5265]

@@asissingh1823 Please don't! I was young and naïve, I didn't know what I was doing!

[@honeyz6386]

@@audreyandremington5265 😂

[@mageshwaridr.1927]

Sir hats off to u...I was beating my head of not understand some physics concepts then God had gifted me ur videos....itz just osm... Thank a lot...I really mean it

[@radiamoon2395]

thank you so much sir that really help. this video is from 2014 and today i'm watching it in 2019, thank you for posting this video.

[@ECSowmyaM]

And im watching it on the second wave of covid in India (2 June,2021)

[@priscillalk5324]

best physics tutor thank you for making physics easy to understand 😁🙏

[@luandanuredini6168]

khan; how do I give the an advice indirectly hmm? also khan: oh yeah lets make an imaginary student and name him the most basic name ever :D that'll work

[@sanjanavenkatesh9044]

omg! I can't express to tell you how much I want to thank you. This video really helped me out

[@prithak3263]

hahaha good way to remember the formula of resistance. (REPLAY) i appreciate it...

[@karmurmeraman3443]

Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@starbai410]

Excellent teacher!

[@karmurmeraman3443]

touge410 _ kzbin.info/www/bejne/r2KUYaN5fd10n8U

[@karmurmeraman3443]

Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@subhashmodak7890]

Nice Formula to remember.

[@Aviyoyopdx]

thank you mike

[@joshpyburn]

My mnemonic for this is Rick Moranis playing the role of a Canadian general named Pouillet leading a feeble resistance and timidly issuing the demand "Role over, eh." Rho * L over A.

[@danilkinsss]

God bless MIke!!

[@Tee.NZ.07]

not a subject you would normally find under medicine.

[@raquelborn]

Applies to medical engineering. Need electricity to power implants.

[@jivra]

MCAT tests knowledge of physics

[@karmurmeraman3443]

kzbin.info/www/bejne/r2KUYaN5fd10n8U

[@karmurmeraman3443]

Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@youngjunpark8412]

This concept is applied to understand ion channels and some ion channels are targets of medicine.

[@siva7930]

very good explanation.thank u 😍

[@kasperbaun]

Really awsome video.. thanks alot !

[@bibijohora2061]

My confusion has cleared... Thank a lot sir...

[@yourfuturedocburenbeiya]

I like the "replay"; thank you so much!!

[@Jamesyoung450]

How isn't your channel more popular?

[@walkthroughonthego2476]

you kidding?

[@therock2730]

marvelous teacher thank you soooooo much finally my doubt cleared keep uploading such a awesome videos

[@karmurmeraman3443]

the rock Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@karmurmeraman3443]

kzbin.info/www/bejne/r2KUYaN5fd10n8U

[@vince6829]

Nice explanation. Thanks for sharing.

[@ariestheram9326]

thanks mike

[@saeedalminji4821]

thank you so much i passed grade 12 becuase of u

[@pridhisoni3789]

This video was just on fleek✨

[@SpeakerWiggin49]

Great video. I just wish we had a different way of describing current pass-through to beginners other than "flow." Electrical current doesn't "flow" through wires like water in a pipe, if anything you can say that it "flows" _into_ the wire when voltage is applied. After the equation for energy and resistance is understood, we should stop discussing conductivity and resistivity with the word "flow" in reference to current attached to parts on the circuit.

[@ShrirangChandankhede]

best lecture on youtube

[@smoke-tt1sr]

Thank you!

[@haripriyadebnath7969]

Thankyousomuch sir!

[@howcreated_ideas]

Thanks for sharing..

[@Adihaivai]

LORD MIKE !!!!!!!!!

[@soniaadetu4560]

Thanks so so much

[@steffliot3788]

Thanks a lot. This video is so so so helpful. Thankyou.

[@basz7802]

this helped so much cheers boss

[@studybuddy5066]

Thank you. It really helped.

[@serene9532]

...is it really pronounced "REE-zistivity"?! Gosh I've always said it normally like "resist-ivity"

[@ebhojayejuliet9728]

You're really good but organic chemistry tutor is goated 🐐

[@ritvikasingh9273]

Nice explanation

[@oscarjrdepamaylo3673]

REPLAY hahaha. I won;'t miss it anymore

[@hypencomics6379]

Sir you are doing great job

[@nnekaokehieson8505]

What did you do with the pie sign when calculating the resistance

[@pierrzmalaka]

Would you know how to calculate the resistance of a distilled water mixed with salt? How can I reach a certain resistance in a solution of salt and distilled water?

[@PressPlayObey]

My favorite channel :)

[@Scientificeducation785]

nice explanation..

[@hankmoody9023]

how come the fluid has a slower velocity on the right hand side as opposed to the left? Is it only due to friction or are there some other underlying reasons?

[@briandahl1659]

1:56 - You state that changing the shape of the resistor will change its resistance. This is a common misconception. If all other factors are held constant the shape does not affect the resistance. For instance a square wire would have the same resistance as a round wire if they were identical in all other regards. This misconception comes from the thought that if you change the shape you necessarily would change the cross-section (size) of the conductor. This isn't necessarily true as you could have a square wire with the same cross section as the round wire.

[@katobrent2031]

overthinking it🙄

[@dawood.jarral]

Thankyousomuch!!! it cleared so many questions..

[@dawood.jarral]

basically something good at conducting is bad at resistivity and vise versa.. so simple to remember..

[@karmurmeraman3443]

Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@thoughtsespresso6348]

i lovve youuuu...thanks for clearing my concepts !!!! *-:

[@chandsikumar309]

Hiii...

[@jahnaviketha9153]

@@chandsikumar309 simp

[@meganbermudez299]

we all gotta clap for Mike

[@sohamjain6206]

How can you quantitatively derive to the resistivity if not given? (plz respond if you know)

[@honeyz6386]

R=v/i

[@mritunjay2624]

Thanks

[@jagadeesansri6711]

Thanks u

[@jagadeesansri6711]

Say slow sir

[@Dev-dn4uu]

I love you mike -Yoel Romero

[@Gjcbox_Obob]

Hey how did you do the calculation at the end? This math is so f*cking complicated for me! Pls explain to me if anyone is reading this comment.. 🙏

[@WalterWipe]

Basically, the equation gets rewritten with the letters "P", "L", and "A" getting replaced with what they represent in the conducter. The "P" represents the resistivity of the metal. As stated in the question, the metal has a resistivity of (i dont feel like rewriting that). Because resistivity is measured in Ohms, the symbol is written next to it. Then, that amount is multiplied by the total length of the resistor. Next, you have "L"/"A". L, which represents the length of the wire, is replaced with the total length of the wire (12m). A, the area of the base of the cylinder, is replaced with the equation for finding the area of a circle (pi * r²). You are given the diameter (0.01m), so you convert it to a radius (divide by 2), getting 0.005m as a result. The final equation for "A" is pi * 0.005m². After that, you put in your calculator the full equation of (1.68 * 10^-8 Omhs * 12m) * (12 / pi *0.005m²). I hope this helped with whatever part you didnt understand. I'm only in 7th grade now when I'm explaining this and I dont know too much, but I can still try and help you with any other questions you still might have.

[@WalterWipe]

Uhh that actually didnt fully work so idk how he got that answer. I dont have a calculator for this stuff.

[@freshsuzuki4014]

amazing

[@Randomperson-tu5we]

I'm only here to understand this more so I can explain it to my uncle because he doesn't understand maths or physica as well as I do 😭 I never thought I would be doing something like this on a weekend at the age of 14

[@ashrayiyer1166]

why da heck ur uncle wanna learn physics

[@bdasaw]

damnn Mike a real nigga

[@thatomofolo452]

R(x)=x/+x

[@ray8417]

I remember "R*A=ρ*l", so rapol or rapl

[@nigeltims8781]

how does an ohm meter measure resistivity? i cant understand this logically

[@pragyakhanna3331]

According to his explanation, ρ= R x A/L So by just placing the units- The unit of Resistance is ohm The unit of area of cross section A is(metre)^2 The unit of length is metre Which gives, ρ= ohm x (metre)^2 /metre ρ= ohm-metre ( Ω metre)

[@adityaprakash8393]

logically understanding units in physics is pointless for many of them.think about momentum 'MV' ,MAKES sense? like simple standard 1multiplication is repeated addition,no! units are mathematical artefacts to maintain the ratio dependence

[@hassanakhtar7874]

At a higher level units start to feel less intuitive because they are a result of making sure units on the right equal units on the left. That being said, intuition behind units is arguably just a result of our brains being used to simple equations like speed = distance/time. Dont get caught up on it.

[@changingspiritually9540]

Thank you but next time make sure there is no black and white as people can be dyslexic. Make sure the writing is in a color friendly for dyslexia.

[@chetalibhawsar4326]

you write (0.005)^2 square as ( 0.0026) instead of writing (0.0025)

[@bimarshadhikari5662]

Well, that result might be something that's a calculation of the whole equation.

[@saniabatool6000]

Why resistivity is not zero at 0 °C ??

[@nusratmoni7310]

u can't understand ?

[@RawDoggin_78]

me, a non native who didn't know the difference between radius and diameter, looking at the last question: *thanos voice* reality is often disappointing

[@P.vishnudutta]

Repla

[@kaifansari7482]

Too hard made by you

[@JP-xm3qf]

What happened so Sal? I want to hear his voice as usual, this person speaks too fast and doesn’t explain as well, should be re-done by Sal!

[@karmurmeraman3443]

Julio Padilla Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you

[@Andrew_Tate_Personal]

geeks

[@kagogoveya6213]

V=IR is not ohm's law!!

[@Cat-qn7pm]

Kago Goveya en.wikipedia.org/wiki/Ohm%27s_law

[@psaven]

+Cat Anderson In some places U is used for the voltage i.e. U=RI

[@amarpreetsingh6394]

+Kago Goveya..... it is the law of ohm where R is the constant of proportionality

[@dalenassar9152]

Your REPLAY trick is ok but it is NOT the way to teach, in a technical school, the PHYSICAL MEANING of resistivity (rho). The students should first be taught to consider a length of wire (as solid cylinder) in which the electrons flow. When you think of a cylinder, what are it's two main parameters? (I asked several people about this and got the SAME answers: HEIGHT,L, & RADIUS, r). Common sense tells us that the longer L is, the higher the resistance, and the larger the cross sectional area (proportional to r^r) the less the resistance. So, resistance is directly proportional to L and inversely proportional to the cross sectional area, A. So R~L/A. And the proportionally constant is rho. So, forming the equation, R=(rho)*L/A.

[@karmurmeraman3443]

dale nassar Hallo friends Plz subscribe my youtube channel for various electrical concepts and objective ques. Which are usefull to you for your any electrical exam and study purpose Thank you