what exactly ‘‘banana’’ means in this context?
can anyone please explain what banana means in this article.
@Gawin: Great question. The surface is an invisible boundary inside the field we’re considering (i.e., if you have a soccer goal, the entire front plane of the goal is an invisible boundary, and the “flux” might be the quantity of soccer balls passing through).
@Nick B: Great point. There may be some subtleties of flux vs fluent that I’m missing. Flux itself might be a rate (bananas/sec) vs just the amount going through (bananas). It likely depends on the application.
@azhar: The banana is whatever your field represents. Usually we talk about an abstract “field” but I prefer to imagine something passing through a boundary. It could be bananas, water, gravitational pull, etc. (bananas are easier to visualize than gravitational pull).
Although I like the basic explanation I think you overlooked one thing: what you call flux is in some domains called ‘fluence’. The fluence ‘rate’ is called ‘flux’. Just have a look at the Wikipedia pages. Since I’m working in a radiology environment where X-rays are going through areas, I’m used to think about flux as the amount of X rays going through an area in a certain time.
hi,
I am studying this subject but I’m struggling to find whether there is a negative or a positive flux. because if you change the poles of a magnet, the flux also changes, what is the relation between them ?
@azhar: No problem! Yep, banana is the fruit – I just used it as a silly example of something that can pass through a surface. We usually talk about electric fields, but something more tangible might be simpler to visualize.
@mustafa: Flux can be positive or negative, which represents whether the field is entering or leaving the surface. Usually with magnetic fields, we imagine the North pole “emitting” the field and the South pole absorbing it. So if you flip the poles of a magnet, the direction of the field changes, and it goes from emitting to absorbing (in the region we are measuring the flux).
Kalid,
Thank you so much for writing up this series! I must send my 11 year old nephew here. I’m on a self study path from GCSE to post degree - might take me a while but your site, I think, will shorten how long it takes for me. So, nice one!
Thanks Richard! Very glad you’re finding it helpful :).
First comment of this year .Whoa! terrific work . I had been looking for such type of perspective on science/maths. I have shared it with with friends. It was also interesting to read the comments and how people pointing out the nitty gritties and mistakes and more importantly,your patient replies.
Actually,I was searching for the similar type of perspective on chemistry.THOSE HELL EQUATIONS.
all rote!
how we can to estimate of divergence, gradient and fluctuation of the people density or flux of people?
“Eventually, we get zero flux when the source and boundary are parallel”
I think you mean perpendicular.
“Like we said before, if the surfaces are parallel, then there is zero flux. If they are perpendicular, there is full flux.”
I think you mean:
if the surface and field are perpendicular, then there is zero flux. If they are parallel , there is full flux.
@Jim: Great feedback, I just clarified. I was thinking of the surface itself being parallel to the field, vs. the normal vector. I’ve included some diagrams and a note to make this more clear.
I love your blog and your imagination. Your examples definitely help to integrate the theory and they’re often wonderfully silly which is a much needed break from the regular abstract rigorous mathematical texts.
Most modern textbooks are awful. There’s nothing worse than loving mathematics and going to class and being given all the answers with no ounce of motivation or applicability.
Thanks MR, really appreciate it. Yes, so many textbooks seem to forget what it was like being a student who wanted to genuinely understand and enjoy the material. It’s never too late to make our own versions though :).
Someone posted about the ‘flow of flux’.
Several textbooks use this terminology and it has always driven me nuts. Certainly the flux itself is not flowing. The flux exists and tells us how much flow we have of the ‘whatever-it-is’.
This is a well written article!! The visualization is clear and very helpful. Vocabulary was kept simple! Made me have a better idea of flux
i really appreciate u sir,for simply clarifying the douts. i have one question sir,what is the use of flux?where it is used?and why to use these? explain me in brief sir,practically
I feel like wow after I read this article but I feel little problem how flux depend upon angel
How would one go about finding the largest source of flux over a surface?