Physics 45 Electromagnetic Induction: Faraday's Law and Lenz's Law (1 of 2) Introduction
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- Опубликовано: 26 мар 2013
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In this first of the two part series I will introduce Faraday's Law and Lenz's Law so you can better understand the concepts and equations.
8 years later since the video was posted! I watch this now and it helps so much, as I was confused how to decide the induced current’s direction. Thank you so much Professor!
Glad the video was helpful. Physics doesn't age. 🙂
Stephen,
In Lenz's words: "The direction of any magnetic induction effect is such as to oppose the cause of the effect"
In other words: "the induced magnetic field will oppose the effect that caused it in the first place", or: " the induced magnetic field will oppose the change".
Thus if the magnetic flux through the loop is decreasing the induced magnetic field will be in the SAME direction as the diminishing field (to try and keep it from decreasing). If the magnetic flux through the loop is increasing, then the induced magnetic field will be in the OPPOSITE direction (to try and keep it from increasing).
Amazing explanation.
what if I have coil and permanent magnet and moving them to a conductive object. why dont they joint ?
Summary of this video (:
Thank you sir
@@mikehawwke
Lenzs law Based on
Conservation of Energy
Keep up the good work professor! If you could see all the people you've helped with your lectures in one area, you would need a whole stadium!
Sreya Panda,
Remember that the induced magnetic field opposed the CHANGE in the magnetic field that caused it in the first place.
If the existing magnetic field is INCREASING, then the induced magnetic field will be in the OPPOSITE direction.
If the existing magnetic field is DECREASING, then the induced magnetic field will be in the SAME direction.
why is it that sir?
sreya panda
Sreya Panda,
The why questions are the most difficult to explain and comprehend and often require advanced science and mathematics to answer,
If you are interested, the playlist on Maxwell's equations explains the answer to your question, but it requires some level of understanding of mathematics
Michel van Biezen thank you so much! ill definitely check it out sir. :)
I did not understand the direction of induced current
thanks dr. for that clarification,you're the best
Dr Van Biezen, you are a life saver! This is the cleanest explanation of the concept of Lenz's Law!
this is the best explaination of lenz's law on YT
Thank you. Glad you found our videos.
I was really not understanding Lenz's law until I watched this lecture. This made a difference in not getting overstressed before the finals. Thank you very much for saving my sleep!
You are welcome. Try not to stress over the final. 🙂
Sir, you did it again !! From helping me understand lenses in optics in my first year of university, to helping me understand Lenz in my 3rd year of university! Thank you Professor!
Great! Glad you came back for your next semester in physics. 🙂
This is a crystal clear explanation of Lenz's law. Many thanks!
This is the simplest explanation to determine the direction of the induced current I found on RUclips.
Thank you, professor.
Glad you found our videos. Welcome to the channel! 🙂
Thank you so much for this...I go to Stanford and our professor for Electricity and Magnetism is terrible. You are so much clearer and easier to understand!!!!
thank you so much for all your help. ive been watching your videos through college phys 1 and 2 and they have saved me so many times!
You have helped me understand some important concepts in physics. I need this to continue my studies in engineering at the university so that I can get out out the clutches of poverty. Thank you. Your work and talent will never be forgotten.
Glad we could help!
My goodness you made it so easy, I was totally lost in the class. Thanks
+Farzad Jalali Hehe, mee too! :) All the standard textbooks I've seen have made every effort to blur this simple point miserably, by using totally confusing, dry, non-expressive language and lame examples, as if this was a patented idea or if the nice & simple explanation costed a fortune. ;)
I was very much confused in this topic. Your video helped me clear my doubts.
Thanks a lot Sir!!
The best video i have saw to understand this law. Excelent! Thank you!
Glad it was helpful!
first class lesson, best i've ever seen or heard. clever choice of examples too.
Thank you this is so great! I take IB Physics and there's a lot of material to cover, so our teacher rushes over it (with terrible handwriting and diagrams) and assumes that we'll figure it all out from the book, but I just learn this stuff so much better from hearing and visualizing than reading... Thanks again!
That is why I keep making these videos.
Thanks for the comment.
after many hours studying i can understand what is all about Faraday's Law and Lenz's Law. Thank you for sharing this video
I WISH you were my phyII professor! You're very clear and organized.
Dear Mr.Michel van Biezen, Nice lecture and many thanks for you.God bless you!
nice one. I am having my physics O levels tomorrow. I guess this helps me clear doubts. You nice man
I really appreciate all the videos, always so helpful and informative!!!!
An easy way to understand the 'decreasing' case is this: assume the South pole of the magnet is moving downward, below and away from the loop. That means the space in that region is declining in South pole flux lines, or equivalently, could be seen as taking on more North pole conditions - it's becoming 'Less South, so relatively more North'. That explains why an 'approaching North pole magnet' and a 'decreasing South pole magnet' require (Lenz's Law) a North pole manifesting in the loop to counter the increasing North pole conditions. In essence, the 'decreasing or moving-away South pole' is like a growing North pole.
It's akin to thinking of the South and North magnetic field density on a continuum - like on a number line - as it is along the length of a bar magnet.
A good way to look at it.
don't know why pay like $1000 for Physics class if my teacher can't give a coherent explanation.
Oh my God, I understand now. Thank you and God bless you
Very clear!!! Congratulations!!!
Hi this video is probably the best video i have seen on this topic, very clear and well structured. I was however confused by your second example where the B field is in the same direction as the induced B, this made me confused as to the link with Lenz's law which states that it would be in the opposite direction. Could you please tell me why you did that?
Besides the great job helping me understand Lenz's Law, I dig the bow-tie.
Thanks a lot. Your way of teaching is wonderful.
Sir, You explained it so simply, so clear and well. Sir, you just gave me hope I might pass the class. I really have trouble grasping the concepts in class. if I had You as my professor, I wouldn't have to worry about passing.
Thank you. Glad you found our videos. Yes, not all professors are good at teaching, unfortunately. We had our share of them when we went to university, although we also had some very excellent professors as well. We do remember the frustration we felt when we couldn't understand the lectures and we were desperate to find a source that could help us. That inspired us to make these videos. All the best on your studies. 🙂
Very helpful, your videos are greatly appreciated! Thank you!
Great! I had not understood this topic until your explanation
Kubra,
Any time the magnetic flux changes (increases or decreases), the will be an induced Emf.
Now I understand sir, thanks a lot,no words to say
Youre such an amazing teacher ! Thank you :)
i'm your old student sir
you are a gift for students specially in this pandamic situation where every student is struggling
Thanks!
@@MichelvanBiezen oh sir happy to see your reply, I mean at least I was not expecting that beacuse the uploaded video is 6 years ago.
Stay safe and happy sir,
Love from PAKISTAN STUDENTS.
Thank you!! This was absolutely perfect.
He actually made it a lot more complicated then it is. If you're approaching the conductor from the north side (negatively charged), the particles in the conductor will move in the opposite direction of the clock, if you do the inverse, if you move the magnet away from the conductor with the north side still facing the conductor, the flow will move in the direction of the clock. The opposite happens with the south or positively charged side.
This video is a lifesaver.
Sir thank you very much for ur videos, they have been a great helt for me
Very clear and so helpful. Thank you!
have to be honest, this guy lectures better than my professor
many thanks for your videos!
Thanks! Now I finally understand! :)
thanks a lot.... extremely helpful!!!! loved ur way of teaching... :)
Change in Magnetic Flux - lines through the coil will INDUCE emf in the coil,
that INDUCED emf will cause an INDUCED current in the coil,
that INDUCED current will set-up it's own Magnetic Field which opposes the change that causes in the first place.
Sir hats off ur explaination is excellent
Thank you so much. Nowadays I am using your videos a lot since I am teaching Physics online due to pandemic.
That's great Hang in there. We'll get through it.
good job!! iSo clear for me to understand the Lenz law.. #Keepitup
Superbly explained. Thank you.
Great review for me...I'm watching the series on Maxwell's Equations. Great background info.! 😊
Yes, this is part of it.
Thank you Sir this HAS helped me ALOT.
I FINALLY understand it! THANK YOU
Very thoroughly explained, thank you so much!
Thank you so much for the youtube channel name (met you on the southwest flight from LA) really helped me out! (:
Jennifer,
Glad these videos are helping. Thanks for letting me know.
Good luck with your exams. Keep up the hard work.
much love from ethiopia. the legend!
Thank you. Welcome to the channel! 🙂
that was so helpful!! thanks heaps
Well done, this was the only part I was little bit lost in my physics class.
God bless u sir, for helping me understand this concept! You hv certainly helped alot of us.. :D ~ all the way frm australia...
Emi Stephen,
It is good to know that students from "down under" are watching these videos.
Thanks for letting me know.
Good explanation. Wanted to know & I found out.
A RUclipsversity student.
Massive thanks from me to you Sir. You helped me again. God bless!!!
You are most welcome. Glad you find our videos helpful. 🙂
thanks this helps a lot! i was struggling to find the current direction before watching it.
Glad it helped!
thank you very much for this video, its really helped me
Very Helpful! Thank you so much :)
Thank you this was really helpful
Thank you for this very clear explanation
THANK YOU I FUCKING LOVE YOU!!!!!!!! I was literally just crying in frustration over this damn concept and watched this video, went back to my examples and made a breakthrough. Chris Paul=Point God, Professor Leonard= Math God, Michel van Biezen= Physics God
your best then my teacher
thanks a lot
Dear sir! I think I found what I was looking for =)) Thank you.
Glad you found ut.
Thank you very much. Keep up the good work
5:27, I don't get it. why is it in the same direction..
The magnetic field cutting throw the wires is decreasing as the magnet is pulled(away) from the loop. Therefore, the current produced in the loop has to oppose decrease in magnetic field(lenz law)...and thus vectors will add up if current is clockwise....
Magnet pulls away(less magnetic lines)....emf induced in loop to oppose the decrease......current is clockwise to add vector fields to the magnetic pulled away from the wire.....If it doesnt oppose then we have created energy outmof nothing, you pull a magnt in, and even more magnetic force keeps adding infinetly.
great explanation!!!
A best explanation ..👍❤️
Thank you 🙂
Professor van Biezen,thanks again,suppose a solenoid with length L, z symeric axis,z(0,0,L)
coil length L, at z=0,stopper and mag. field N ans reversing, plunger ferrite magnetization
partial as per hysteresis remannecence, plunger legth =h,what is relative TD and BDC of plunger inside the solenoid, z coordinate from 0, and ha stroke end of plunger? x(t) and Dx(t)/dt, and d2x(t)/dt2, Bsol-Bemf=B? Thanks and Regards
Great description thank you
Glad it was helpful!
You have so many faraday law videos, idk which one to watch
You probably want to watch a handful of them, to get a good understanding of the principle.
EXCELLENT, THANKS VERY MUCH
thanx a lot it is really helped me to understand it ..
thank you i really appreciate this
Thank you so much that was really helpful!
Glad it was helpful! 🙂
Remembering the energy is conserved helps understand this.
Thanks a lot for your lecture, you really made it so easy. I appreciate it a lot. I just want to understand the difference between figure 3 and 4, as i am confused about case3, i think it might be North going outwards the solenoid. Again thank you very much for your structured way of explaining.
Figure 3 and figure 4 are essentially the same in that the magnet approaches the loop with the south pole pointing to the loop, except that in figure 3 the magnet approaches the loop from below and in figure 4 the magnet approaches the loop from above.
I think there is something wrong in your diagrams between Figure 1 and Figure 4 - please look at these diagrams again, @Micheal van Biezen. I think it has to do with the magnet force you drew in Fig. 1 the magnetic flux is increasing but pointed in the wrong direction- according to your diagram. Since the magnetic flow is flowing into the North pole of the magnetic, and not out of it, as you picture it - if I'm correct. Thank you for all your hard work Dr. Biezen.
Very smart lecture
Very intelligent and clear explanation
Glad it was helpful!
U made it so easy sir. Thank u👍
Most welcome 😊
Thank you so much. Such a clear explanation tq
You are welcome 😊
Bro really helping me to score Physics
Glad you found our videos.
thanks.. it really help me :D keep it up sir
Hello teachers, I have questions
The magnetic field shown in Figure P20.63 has a uni- form magnitude of 25.0 mT directed into the paper. The initial diameter of the kink is 2.00 cm. (a) The wire is quickly pulled taut, and the kink shrinks to a diameter of zero in 50.0 ms. Determine the average voltage induced between endpoints A and B. Include the polarity. (b) Suppose the kink is undisturbed, but the magnetic field increases to 100 mT in 4.00 3 1023 s. Determine the average voltage across terminals A and B, including polarity, during this period.
AB
Push magnet through loop and you reverse thumb rule.
Pull magnet away from loop and you keep it same thumb rule.
luv it !!
the interactive force is the magnetic force of repulsion(b/w induced mag field and pre existing), that said as opposing flux change. isnt ?
Jamie Nakrani From what I understood... Imagine if, when you moved a magnet away from the loop of wire, the induced current created a magnetic field that pushed the magnet further away. That's kind of a problem (Law of Conservation of Energy, for one). So obviously, the induced current has to produce a magnetic field that will pull the magnet back towards the loop - it is resisting the change.
I love you!!!!!
Hello Professor Michel Van Biezen, the way you explained it was so clear, that I understood it, and I was thinking of an analogy of a BOXING MATCH of Manny Pakman Pacquiao exchanging blows with MARGARITO .... something like that .... hahahaha
A good analogy. 🙂
Thank you so much
My left ear is an Electrical Engineer.
thank you very much sir
Excellent lecture Sir 🙏🙏🙏🙏
Thanks and welcome
thank u bro 4 da lesson
u kno g neva capo in 💯💯💯
Glad you liked it. 🙂