Courses on Khan Academy are always 100% free. Start practicing-and saving your progress-now: www.khanacadem... Introduction and intuition for flux and magnetic flux.
Sal is the best instructor ever. I have watched all his math and physics videos and NOBODY can teach like he can...and he is an artist, too, so his diagrams are great, too.
We all know this is an extraordinary man and channel. But this video just blew me away, it sounds simple now but it looked crazy before, that is teaching perfection.
Please do a video on flux density, and also the difference between B and H field? :p Anyway, great video once again. My teachers this year have been absolutely awful (the books weren't any better as they were written by them), and I cannot express how grateful I am for having been born in a time with the Internet, where free knowledge - WELL explained knowledge - is available to anyone. I have always been something of an autodidact or self-directed learner, and I have always done well in school. However, these last past years I have lost much faith in the education system. However, I still like to learn - just not in school anymore, I honestly dread it - and because of people like you (and others, like DrPhysicsA or Ben Eater and many, many more), this has not only become possible, it almost has become an addiction, a necessity to me. When I watch your videos I feel like understanding almost everything immediately, and in a way where I suddenly re-remember the importance and greatness in these discoveries of our physical world, and I finally feel the true spirit of learning again. Your website is a sanctuary, a place where knowledge and learning aren't related to your gender, your age, your intelligence, your interests in pleasing teachers or whatever. It's just.... pure learning, raw naked. Without biases, without anyone judging you for anything, without anything else. And that's how it should be. Everything I have done >really< well in school has started with you. I will never have more respect for people like I have for people like you. I have no doubt that I will continue learning after my graduation - but this time, for real. Without wasting time on doing stupid stuff to please the teachers and the 'system'. So once again: truly, thank you.
So much better than the 5 second glossed over definition on Bozeman science which was something along the lines of "it's how much a conductive material reacts to a magnetic field. Like how you react to sunlight." And that was literally it. It was in the video on induction. I got completely lost after that and had to seek out other resources.
I think magnetic flux & magnetic field are 2 different entities. Magnetic flux is a scalar qty. measured by its density while magnetic field is a vector qty. shown by line with arrow. Both, flux & field follow inverse sq. law. A magnetic pole has flux around it. Magnetic field which is force field appears only when flux of one pole interacts with flux of other pole. Since there is no monopole magnetic flux & magnetic field co-exist around a magnet. Change in flux density & motion of flux produce all forces & motions.
I normally never comment on any RU-vid video but this one is just amazing. I remember watching your video about spring constant when I was a freshman and now I'm 2 months away from graduating high school, and I would've never made it without you. Thank you sal, thank you dearly.
Working on it. I'll have a video up in a couple of weeks explaining the theory behind a flux capacitor. It's a follow up video to this one I made... ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-GWiKGiK_iQI.html If you're a fan of BTTF, and you're still reading responses to a comment you made a year ago, I think you'll like it.
I'm not clear why an increase in speed means a higher flux? 2:50 you say higher speed means "more things going through that surface" but is that true, where can I learn the explanation for that? If the density is the same, and you plunk a net down, the "things" that go through, go through faster, but do more "things" go through?
Flux is defined as flow of something per unit area per unit time, so when stretching the "net" to increase area, flux can be reduced. So it's about how we define flux. Great video. Pls make some video explaining types of magnetic material. Thanks.
Assuming the flow per unit time is constant and the amount of flow of the material is the same before stretching the "net". Then yes, the flux is reduced.
Doubling the size of the net will not double the flux. It is flow per unit area. The only way changing the size of the net will change anything is if the flow is uneven and the expanded net captures flow moving at a different rate. It's like saying I ran 1 mile in an hour, than I ran two miles in two hours, so I'm running faster now (not really)
Might as well add electrical induction into this lesson. The amount of magnetic flux that is in relative motion next to a conductor induces voltage onto the conductor. This is how we generate electricity.
Is there a definition for a SINGLE line of flux? For example, this would allow us to state exactly how many LINES of flux passes through a square meter in a uniform magnetic flux field of, say, one "Tesla" perpendicular to that flux field. THANKS FOR, YET ANOTHER, GREAT VIDEO!!
Hey and what if you increase the area but to towards a region where magnetic field lines didn't exist? Logically i would say the flux won't change, but wouldn't it increase by the equation ABcos theta? I appreciate a quick response
what an amazing video it was....though i knew about the magnetic flux before but it widens my previous knowledge so very much.....thanks sal khan ....proud to be a bangladeshi
You've been helping with through math and science since I was a wee little guy and this is the last video in the electrical physics playlist so there arn't any more videos here for me. Thanks so much man you've saved my life (test grades) its been good learning from ya (:
Nothing is "Physical". Everything is "information". Your magnetic field is not any less "physical" or "solid" than your "water", which is also pure energy flowing.
Pleaser anybody help me. Is the magnetic flux, the density of the magnetic vetors? or the size of the vectors? Or a product of both? Sal Khan, mentioned that the flux is how many are perpendicular to the surface. but if you tilt the surface, then no vectors are going to be perpendicular to the surface.
yes but if flux simply relates to amount of particles crossing a given area over a given time, why does flux cancel each other when it's in the opposite directions?
@@zaphrode4110 yeah ! 1 resistor . 5 amps flowing into the left side and 5 amps flowing into the right side . Math model : ( + 5 ) + ( - 5 ) = 0 amps or ( - 5 ) + ( + 5 ) = 0 amps . 0 amps total quantity Net current . Use KVL , Ohm's law , passive sign convention to fill in the extra details of those equations . Push on a wall with the same force on each side . Net force on the wall is 0 . Distribute multiple but identical forces on each side of the wall( surface ) . Net force onto the wall is 0 . Combine the forces with + . while the direction ( Vector Arrow ) is given a + or - , as shown above . Maybe "a plastic bottle" was trying to ask something else ? Flux lines , can depict Quantity( amount ) , direction , who knows what other parameters are embedded in a Flux depiction( I suppose it depends on the complexity of what is being visually modeled ).
The rain has abated and pollutants that were in the air have been grounded. Things around me can be seen more clearly now, but as electrons in obscene amounts whiz by me, through copper wires, as the power meter counts them over time as I listened to the sound of the electric fan in the heater blowing warmed air towards my person to reduce the chilly sensation of the cooler oxygen atoms take up the heat given up by my body, as I let the video on the topic of magnetic flux play to its end, I was left wondering - What is magnetic flux? Magnetic flux can be likened to water flow in a river, fed by tributaries upstream. Flux can be imagined to be flowing as tributaries carrying water to a stream. The deeper the stream, the greater the pressure at depth. Magnetic flux condenses with the greater number of flux lines of force, making a greater strength of magnetic attraction and repulsion. Through the air, flux lines tend to separate, but when channelled through a piece of iron or a metal bar the flux lines consolidate in the given metal, leaving no loose ends in the flux field to go astray, but they can be made to follow the desired path. I am the original concept design creator of what I believe has later become used in the design of the Tesla EV motor, so I considered the explanation given of magnetic flux to be a lot more confusing for people new to the subject than it needed to be.
I'm so confused because if you calculate the flux, and you apply gauss law in the magnetic field, it gives you the divergence of the magnetic field, which we know is zero because of the propriety of magnetic fields, please someone explain me what am I missing
A limited area of knowledge or Endeavour to which pursuits, activities and interests are a central representation held to a concept of physical theory. In this way, a field is defined by the distribution of a physical quantity, such as temperature, mass density, or potential energy y, at different points in space. In the particularly important example of force fields, such as gravitational, electrical, and magnetic fields, the field value at a point is the force which a test particle would experience if it were located at that point. The philosophical problem is whether a force field is to be thought of as purely potential, so the presence of a field merely describes the propensity of masses to move relative to each other, or whether it should be thought of in terms of the physically real modifications of a medium, whose properties result in such powers that are, liken to force fields, having potentially pure characterized by their means of dispositional statements or conditionals, or are they categorical or actual? The former option seems to require within ungrounded dispositions, or regions of space that differ only in what happens if an object is placed there. The law-like shape of these dispositions, apparent for example in the curved lines of force of the magnetic field, may then seem quite inexplicable. To atomists, such as Newton it would represent a return to Aristotelian entelechies, or quasi-psychological affinities between things, which are responsible for their motions. The latter option requires understanding of how forces of attraction and repulsion can be grounded in the properties of the medium. The basic idea of a field is arguably present in Leibniz, who was certainly hostile to Newtonian atomism. Despite the fact that his equally hostility to action at a distance muddies the water. It is usually credited to the Jesuit mathematician and scientist Joseph Boscovich (1711-87) and Immanuel Kant (1724-1804), both of whom was influenced by the scientist, Michael Faraday (1791-1867), with whose work the physical notion became established. In his paper on "The Physical Character of the Lines of Magnetic Force" (1852). Faraday was to suggest several criteria for assessing the physical reality of lines of force, such as whether they are affected by an intervening material medium, whether the motion depends on the nature of what is placed at the receiving end. As far as electromagnetic fields go, Faraday himself inclined to the view that the mathematical similarity between heat flow, currents, and electromagnetic lines of force was evidence for the physical reality of the intervening medium.
Air "Gradient" , like in image editing gray scale from full white( max density , to gray , lightly dense ) . Read book ISBN : 0-07-027406-1 "Engineering Electromagnetics" 1989 McGraw-Hill . page 45 , 47 , 52 . Streamlines or Flux Lines , or Direction Lines . "Flux" is a very old-time word , circa 1350 to 1400 by now , Flux is in the public domain . All done in Europe . To get a more complete definition of Flux , look it up in a dictionary ( i did ) . Flux isn't just used with electrical phenomena . The above book does discuss how Flux is used to describe the visual interpretation of an equation of a family of curves . When working with magnetism , the Flux lines would be called: Magnetic Flux . If the equations were modeling Electric Fields , the Flux lines ( Streamlines ) would be of Electric Flux . "Flux" ,...Flow lines , visual depiction of an equation . Electromagnetic Field Theory is difficult . 1600 to 1899 about 300 years of European R&D . It was all done in Europe . Mostly France , England , Germany , not necessarily in that order .
Electric current is the same as the change in charge over time (I=Q/t) and charge being the number of electrons flowing multiplied by the charge of a single electron, also called an "elementary charge" (Q=n*1.6*10^-19) Q = Charge n = Number of electrons 1.6*10^-19 = The charge of a single electron (One elementary charge) I = Current t = Time You can think of electric flux in the same way as Sal explained in the example with airflow. Electric flux is the number of force vectors flowing through a given area over a certain time interval. And the force vectors would then be caused by electrons instead of air particles. Hope this helped! Edit: typo
First and foremost I absolutely love this guy...that being said it drives me crazy when he repeats himself all the time xD. Id probably do worse things on camera but still...something to work on. Something to work on...
I think its good when teachers repeat themselves so I don't miss something while I'm deep in thought and still wrapping my head around what was said earlier.
Flux is not defined as how much of something pass through a surface PER UNIT TIME. Indeed, when you talk about magnetic flux, there is nothing changing over time (if we suppose a constant magnetic field, like that of a still magnet) but one can still define a flux. The point is, your air example is confusing, because you seem to say that the flux is how much molecules of air pass through the surface per unit time, while this is only a consequence of the fact that here you are considering the flux of the velocity vector field. So the fact that in that example you have the "in a certain amount of time" concept is only due to the fact that you are considering a particular vector field, the velocity one. Once you pass to magnetic field there is no analogous "in a certain amount of time", because there is nothing flowing here, and this fact creates confusion in my opinion. So, I think your video is nice, but maybe can produce a misconception about the flux in general, as you can see from some comments.
@@ericj199 to get in a good college... Actually in India there are a lot of people getting a btech degree do getting in some good college is the only thing that can help.
