There's a link to the exam in the description. It is part of the University of Sydney's calendar archive which contains all of the subject exams and other historical details. Petr and I filmed a video for his channel at the same time, check it out here: ruclips.net/video/z1YhlaYQBeM/видео.html
Is it possible to talk to you about minoring or not in physics (current computer science student in undergrad). I'm starting to have way less interests in computer science directly. More interested in image processing, artificial intelligence, physics simulation, computational physics. Minoring or not or double another bachelor..
Steven Mendoza The “Einstein failed math as a kid” myth is just that. He had actually mastered differential and integral calculus by the time he was 15.
@@ahamuffin4747 yeah, it was taken between 1901 an 1904 by a german scholar studying foreign culture. in western world, a photo was serious business, it was like getting a portrait painted. but i was new in china so the chinese farmer had never been exposed to such thing. and so he did an unconventional pose for western standart.
The almost complete absence of abstract questions and problems is very interesting. Almost everything is practical and somehow related to everyday situations
@Daniel Gomez I don't think they're basic in the modern sense. What I'm alluding to is James Flynn's theory that over the 20th and 21st centuries the approach to knowledge and intelligence has increasingly shifted from purely practical and concrete to universal and abstract.
@@Krawurxus Well, I'm not going to do the thinking for you. Knowledge about the nomadic lifestyle might be too universal and abstract for you. Stick to practical knowledge that's useful for your everyday life, like how to turn on the microwave to heat your pizza or how to operate the cash register. Don't think too hard, Darling. Stick to the practical. I'm sorry for challenging your beliefs. That was a step too far and too abstract for your mind
On the question of photography by gaslight: It's not the amount of light, but the color of the light. The silver compounds used for black & white photography are relatively insensitive at the red end of the spectrum - which is why darkroom safelights were traditionally dim red lights. The color temperature of gaslight is around 2900K, which is quite red. So even with lots of lamps to give very bright gaslight, you'd have a hard time taking pictures in 1888. In the 1970s when sodium vapor street lamps were introduced, it was discovered that the light produced - just two spectral lines in the yellow range - was completely invisible to b&w film and paper, and new safelights were produced that made darkrooms as bright as any other room.
good point! The amount of light was always an issue, but by 1880's emulsion sensitivity was getting pretty fast, Eadweard Muybridge was already doing his 'moving' series with something like 25 separate shots per second. edit... I presume this was a specially made emulsion at the time, not in common use, as portraits would be shot on larger format with greater detail, so still slow exposures by today's standard.
Also note that the yellow street lights are actually good for the night sky but the new blueish LED ones are not good. But nobody cares about light pollution.
@@sciencepetr5179 old dark rooms (1970's) had 'safe lights' which were red. (or orange). My understanding at the time was that the red photons lacked the energy needed to trigger the chemical reaction. en.m.wikipedia.org/wiki/Safelight
@@suicidaleuphoria7012 They mean the electrical field and the magnetic field. The motional energy of a charge creates a magnetic field (it is like the kinetic energy in gravitation) which is outside of the conductor. If you calculate the amount of energy contained in the field you'd realise that the seat of the energy of a charge is in the dielectric around a cable. It is barely taught in modern school. Field physics in electric theory sadly has been falling backwards in my opinion.
@@suicidaleuphoria7012 I suspect it refers to the energy stored in the dielectric due to the charge on the conductor polarising the atoms/molecules in the dielectric, thus giving rise to the Polarisation vector. Consider a parallel plate capacitor, with the capacitance given by C = Eo × Er × A ÷ d, where Eo (epsilon subscript zero) is the permittivity of free space, Er (epsilon subscript r) is the relative permittivity of the dielectric, A is the area of the conductor (subtended on the other conductor forming the capacitor), and d is the distance between the conductors. Vacuum has Er = 1, air has Er ≈ 1 (almost but not quite), whereas a dielectric such as rubber has Er = 7. So, a capacitor having a given conductor area and separation using rubber as the dielectric will have seven times the capacitance as that using air dielectric (for the same physical configuration). The energy U Joules stored in a capacitor of C Farads charged to V Volts is given by U = ½ C V². Therefore, for a given voltage and same conductor area and separation, the capacitor with the rubber dielectric will store seven times more energy than the capacitor with the air dielectric. Ergo, one can conclude that the energy is stored in the dielectric. Edit: added mathematical notation courtesy of my Android phone.
@@suicidaleuphoria7012 Yes, they knew about it - by 1888 Maxwell had published his theory on electromagnetism, and Heinrich Hertz was proving the theory by transmitting radio waves across his laboratory!
im still trying to figure what accent you have. it certainly doesnt sound austrailian. im getting some canada vibes, perhaps in the west? like alberta?
1888 Teacher: What is gravity? Me: It's the curvature of space-time caused by the energy that it contains and whose geometric deformation is defined by the equations of Einstein Teacher: WAT? Space-time? Who is Einstein? Get out of my class! Me: Guess you guys are not ready for that yet, but your kids gonna love it
So much of what undergrads know now was unknown even to the brilliant minds back then. I wonder what might be common knowledge for undergrads 130 years from now that we don't even have a hint of.
ekdum sahi, but may be the leap physics made in past 2-3-4 hundred years is reaching saturation, it aint growing fundamentally at the rate, it grew in past centuries. other fields are now hitting puberty...
@@shivamb-s8k I understand what you imply but isn't it also true that the more you find out, the harder it gets to move on to the next level because of the complexity demanded?
I hope we'll have solved the dark matter and dark energy stuff, and have quantum gravitation figured out (or an even bigger theory that contains it). And I wonder if the hints we recently got about what could be a 5th fundamental force are going to bring much to the table
I think even looking outside of undergrad levels of schooling. back in primary school (1995 or thereabouts) we were learning about film exposure on photosensitive paper via sunlight and silhouettes. Things that were once in the realm of advanced science have slowly trickled down into 'regular' science and finally into the public domain as assumed knowledge taught as early in life as 10-14 years old
1:43 by "seat of energy" the question means "storage location of energy" It means to ask us to prove that the Electrical energy of a charged conductor stores in dielectric but not in the conductor. For example, the charged capacitor stores the potential energy not in the conductor of which its walls are made up of but it gets stored in the dielectric medium of the capacitor.
Well we still know Keplar and Newton and Hooke and others, so there's a good chance that Einstein would still be remembered even if physics advances significantly in the next 200 years.
Tobey was soooo yesterday I cant remember what he looks like, but thanks to the internetz... yea the vibe is there. Now! it'll be interesting if we could somehow measure this "vibes". 🦄
Actually I'm very intrigued by this exam, a lot of it is actually applicable to today's physics: . 1. What is the law of gravitation and the proof it is considered to rest - the law that 2 bodies attract one another at a force proportional to the square of the distance between the two bodies: earth and the moon, apple and the surface of earth. (1888 Newtonian Mechanics - can still be applied today for mathematical purposes and is still taught in University Physics today!!) . 2. Faraday and "the seat of electrical energy" question: Is probably a classical example how physics is "warped" by the English language. A quick google and I find that this is a terminology for, ..."reactions at each of the two electrode-electrolyte interfaces provide the "seat of emf" for the voltaic cell". One can write about oxidation and reduction reaction, with the EMF difference leading to voltage generated. Even today we have crazy issues related to physics and language, as an example there is no difference between scalar and vector in Portuguese, yet in the English physics course we dedicate so much time to what is really a language related intellectual concept. . 3. The photographic camera - I'm a little surprised that these students didn't jump at the concept of how light inverts through a pin hole camera and that a gas light source is too weak for this phenomena (although the second student go it right). Also check out my theory as to why people never smiled in photos or paintings below (please note I could be wrong). . 4. a google search and I found that ' Graduated Steelyard' was the name for a 'balance scale'. (why did we change the name?) They appear to be alluding to the formula of 'moments (force x perpendicular distance) - I couldn't read the remainder of the question. But this is a cool physics question, it was ruined by the changes in English. Just imagine how kids in the future will be reading our present day physics questions and asking, "what the hell is a Van Der Graaf Generator?" . 5. What is a magnet and how can you make a magnet? - Using 1888 physics (still applicable today). A magnet is a metal with all the 'magnetic moment' of the microscopic particles aligned. You can make one (at least temporarily) by placing a metal rod in an electric coil and electrifying the coil, this will align the 'magnetic moments' and create a magnet. As I said - still correct today. . 6. The Bell telephone - this is an essay type answer. Based on the principle of voice/sound beating on a surface (microphone) connected to a magnet vibrating inside a coil creating an alternating electric voltage moving in conjunction with the voice/sound down a line and in turn running back through a coil giving magnetic impulses to a magnet connected to a surface (speaker) and turning the human voice into electricity, running down a line and turning back into sound through a speaker. This principle was kept right through to about the 1990' s records, microphones and amplifiers, etc. Again - I kind of hoped these students would get this one. When the young scientists replied with, "I've never even seen a telephone."... my thought was first, "F#$k you, I'm not that old!". My second thought was, no hold on a second - you can still figure this dammit, I think you getting a fail mark. . 7. Okay Nicholson's hydrometer - a quick google and it's a buoyancy test gauge for different fluids. Okay quick one here: - I was actually impressed with reading about this as I use something similar to test oil based inks at my work. As a quick note you have a gizmo that is semi-buoyant with a vertical stick and markings for you to test its buoyancy in water. Mark the stick(where it penetrates the water level) then place it in another fluid and check the buoyancy level relative to water.... AND relative to the temperature. It's actually quite a cool physics test with math models etc, related to viscosity, buoyancy and temperature. Very applicable today and we could do the math and test accurately viscosity of fluids using the 1888 Nicholson hydrometer.
As a graduate in ancient Greek, it has often been impressed upon me how the thought processes of former generations were colored by the beliefs, technology and even the vocabulary of their time. It is an error for us to feel certain that we know what they were talking about just because we can read their words or see images (as in old photographs or even ancient art) from their times. We do not have their context to necessarily decode their thought. Context must come before interpretation.
And the one guy hasn't seen a telephone in his life. WTF? Never used...okay. But never seen? Somehow I also suspect his definition of telephone is a bit off, because they are everywhere around me.
Wouldn't it be wonderful if we actually get to see what the students answered to these questions back in 1880s. Are those records even present in archive?
really? How is that? I know that there is a very noticeable difference in the old exams and modern exams. Is perhaps how the questions were phrased that holds similarity?
@@iiopas9739 I think he's referring to stuff like "how would you build a telephone?" Which is something you'd probably ask an electrical engineer rather than a physicist.
@celine loves loona 이달소 they have an idea but don't dive into specific. For example, the telephone question would be a theory in physics. While the engineering student would give you the length of the wire, wire width, wire type etc.
All the physics exam I have ever taken in my life focused on mathematics and problem-solving. It seems that physics exams in the 19th century focused more on real-world problems than they do today.
You can think of electron spin, in a way, as little electromagnets. Electromagnets work because charged particles in wires going in circles create a magnetic field. Electrons spinning on their own axis, then, also create magnetic fields. Someone in 1888 might get all the stuff I said here apart from the stuff about electrons.
Magnetism is a relativistic consequence of how electric fields are perceived, when the charges causing those field move. Remember, changes in the electric field can only travel at the speed of light. When charges have no relative velocity to you, the electric field travels the way you would expect. If two charges are the same distance away from you, the waves in their electric fields will reach you at the same time. However, once the charges are moving relative to you, the waves through the electric field won't reach you at the same time anymore. This relativistic "skewing" is what causes the magnetic force. I'm afraid I don't know enough to explain it more deeply, but hopefully it gives you some idea. You can always google around if you want to learn more now that you know what to look for.
5:00 People in 1888 did know that magnetic fields come from moving charge. They didn't know what atoms looked like though or what electrons were. Maybe they'd just say certain metals constantly experience moving charges (which isn't wrong)?
5:00 And that's why if you fire up a magnet in a furnace it loses its magnetic properties. Also why some metals get residual magnetism when exposed to magnets.
It's actually a lot of factors. 1. Amount of unpaired electrons in the outer shell. 2. The crystaline lattice structure of the metal. 3 Whether or not the "Domains" of the metal are also aligned. Number 2 is why neodymium magnets are so strong even though neodymium is nonmagnetic. Turns out that trying to find out why Gadolinium isn't the strongest magnet, leads you down a rabbit hole of knowledge.
The reason for the photograph thing is that they were using Silver Halide in those photographic plates. More importantly, it was before the discovery of the dyes that we used to make silver halide sensitive to light other than basically blue light. Gaslamps didn't give off enough blue light to actually take a picture using silver halide plates, both because of the spectrum of light given off by gaslamps was skewed towards the red end of the spectrum and because the amount of light given off was inadequate.
I just love the aesthetic of your videos. The framing of the video with the gorgeous bookcase, portrait, physics paraphernalia is the background is just perfect. It's calming, pleasing, and puts me a mood to get excited about scientific pursuits.
3:35 the sensitivity of old film/emulsions was only one part as to why people would not smile during photographs. In daylight or a well lit studio, there would have been more than enough light to take a adequately fast exposures, even in the 1870s. The more universal reason that we do not see people smiling in photographs is that getting a picture taken in early days was a very serious, expensive, and formal affair. Given this and the cultural understanding of what a picture was at the time, Westerners would have been considered idiotic to smile. In early Eastern photography, btw you can find plenty of Asian men smiling.
I like those questions, because they test your understanding of concepts rather than your ability to memorise and juggle with equations without having a real understanding of what's going on.
3:35 another reason was because they didn't view a picture as much different from a painting which was a formal or serious afair. Not something to do flippantly like we do today.
Q.9 was interesting for me as a professional photographer. I've no idea what the expected answer is/was, but in 1888, emulsions were not panchromatic, meaning they were not sensitive to the whole visible spectrum, and were so insensitive to longer wavelengths of light that they could actually be developed under red safelight conditions like black and white wet process paper still is. As gas light's spectrum is limited to the longer end of the spectrum and contains almost nothing in the blue/green end of the spectrum, exposures under such conditions in 1888 would have been phenomenally long. Also, emulsions in general were very slow, so even with full spectral sensitivity, they'd still be tragically long. Its interesting to note that in 1888, when this paper was written, Kodak were just launching the ground breaking Kodak #1 camera which revolutionised photography as we know it. The reality is, the authors of this paper were probably unaware of this. Even so, in 1888, photo emulsion sensitivity was such that even in bright daylight, exposure times were such that most movement could not be captured. If only the authors knew that within 4 years of this exam paper being written, Q9 at least, would be mostly obsolete, and completely obsolete within 15. So fast was the progress in this arena at the turn of the 20th century.
Thank you for the photo at the end. I am working on a history of Broadway and this photo confirms there was once a substantial natural creek feeding the lake due to the size of the bridge at that time, and presumably the natural contour of the slope before major earthworks in the 20th century. In 1864 it would have been before the cutting was made extending Parramatta Road around the north side of the university, and Parramatta Road would have joined City Road to the south of the uni. City Road also had a different alignment then. It joined Broadway in the same place it does now but from about the Seymour Center it continued directly south and was much further east than the alignment it currently has. The old alignment is where Darlington Road and the part of Maze Crescent that goes from Darlington down to the back of the Seymour Center are now. I see from the photo clear sky through the entrance arch which means that the west wing had not been built yet and there was no quadrangle to enjoy. There is a lot more than just the physics examination questions that has changed.
Gas light would be mostly long waves of light far apart from each other... Similar to the red light of the dark room. The longer waves would not register on the negative. Instead the bright flash is mostly blue light which consist of shot waves closer together. These register better on the negative.
I'm rushing with the explenation of the gas light question. Yesterday I've attendend the "wet plate"/ collodian photography course. The light-sensitive substance isn't picking up red light at all (thats why you can chemicaly process light-senistive image before stoping the reaction under red lamps) and is highly sensitive on blue spectrum of the light (f.eg. blue eyes apear to be brighter). Gaslight is not to dimm, it would just require longer exposure. It is probably emiting red-ish spectrum of light which is undetected by the silver compound of the liquid on your glass plate. I urge you to check this tottaly owesome technique on RUclips. Just look for "wet plate photography". Cheers! :D
The gaslight question is probably due to reciprocity failure in the emulsion. EDIT: Or, as others have pointed out, lack of sensitivity to the red end of the spectrum.
When I realized that "gaslight" is referring to the light source that were lit by gas. The camera aside, Electricity light ain't even common back then.
6. I think this is in reference to electricity only flowing on the surface of conductors, or rather charge accumulating mostly on the surface. That is to say, the charge "sits" on the air contacting the conductor (dielectric).
Photographic film/plates of the era had limited spectral sensitivity (mostly blue and UV) and were basically “blind” to the spectrum of light emitted by “gaslight”
This just shows how for over a hundred years our school systems uses the same things and way developed during that time and nothing has ever changed. The system developed during the time that worked producing liable workers and has carried on to today. I can write for hours but we need to change our system for our kids and our future if we want to stay in this planet for generations.
Oh you are completely right sir. There is nothing wrong with answering questions but what I am trying to say and should have qualified it more was that the way we treat this tests. How much we value over this exams. The amount stress it causes, problems, depression etc. How we use this tests to see about students and judge them in it. Or not. I am not trying to be the hater here but there is something odd about it. 😁
My grandfather, who worked for IBM during the Apollo Program, was excited when I told him that I knew how to use a slide rule. He was less excited when I told him I learned it in a college elective called "History of Math".
I love history and the way people wrote in the 19th century. I read a lot of US history, especially intellectual history, so I get some of this. When they say the "seat of the electrical charge," seat means the basis or source of the electrical charge. The rationale for the word choice is that a "seat" is where something sits, where it is located or rightly located. This is seen in phrases like "the seat of power." The modern word choice would be something like "root," the source of nutrition and vitality for a plant.
3:44 I'm going to give you my theory as to why people didn't smile in photos nor in paintings: They may well have had skew teeth. I think this is one of the simple issues we overlook about time's gone by (before braces).... but I could be wrong. . The painting entitled "Girl with a Pearl Earring" by Vermeer is extremely famous, I believe, because it is probably the only painting in its era to actually show teeth.
2120 undergradulates: Remember when we first learned that the interpretation of quantum mechanics was so stupid and how Einstein's theory was so limiting?
I actually don't think that's the case. Terminology might change a tad and the cultural reference points might shift a bit, but nowadays the stuff we learn at this level is pretty well-understood in a way that wasn't back then.
@@NotaWalrus1 We know more because we have more empirical evidence, but only now did people dliscover evidence for the universe not being flat, and quantum mechanics contradicts Einstein's theory of relativity, and simple things like how bicycle self-right and how planes fly aren't fully explained by science yet. Don't forget that other fields are still not yet to be fully explored like AI or the human mind
@@NotaWalrus1 At what level do you mean? If you're talking about how many subjects in science and technology aren't thoroughly explored 100 percent, then pretty much all of them do. There's plenty to discover in this vast universe. Sometimes we can combine things we already know into things we don't have before, like in material science for example
If the cameras back then *were* using some sort of silver colloidal... would gas lights have given off enough light in the blue spectrum to allow an image?
An 1888 student reacting to 2019 exam? Anything goes really...but an 1888 professor reacting to a 2019 exam? First words to leave their mouth "This is PREPOSTEROUS!!"😂😂😂
Imagine you're a student in 1888 and you are shown a modern exam, with a brief outline of modern theories, but without any of the modern technology to test any of it. You know it's all true, yet it would completely screw you up, undermine everything you knew, all your current thinking... nothing would ever be the same again. How do you prove something if you haven't done the 100 years of ground work that was needed to get there? They'd throw you out of University and possibly lock you up for your own good! 😫
edit - that would be an interesting video: What modern Physics or Math theories could have been discovered / calculated in 1888 with only the knowledge and equipment that existed then? 🤔
@@tibees probably looking back at 2019 exams and saying things like 'I've never seen a 'mobile phone', I think my grandad used to have one, they're funny, you had carry a box and touch a screen to talk to someone!" 😁
The magnetism/'spin' answer is complicated not just because quantum mechanics hadn't been formulated, but also because J.J. Thomson's concept/discovery of the electron wasn't until 1897, so you couldn't even use 'electron alignment' as an explanation.
It’s very interesting reading through the details and names in the calendar. It’s like a factual time capsule. I wonder what became of the students; especially those that received awards and scholarships.
Question 6 would have confounded me 5 years ago... but it's just asking, on what grounds statement, that the basis of electrical energy is within dielectric is true. And yeah, If you think electrical energy flows in wires... WRONG! All the electrical energy is in the electrical fields that flow through the dielectric. That is to say the material between two conductors. Whether it be glass fiber between conductors in a printed circuit board or in the air between two conductors (the live and neutral for example) in your walls. ;)
It would be great to also show what would have been the "right" answers at the time. What would physics students have answered with the knowledge back then?
There's a link to the exam in the description. It is part of the University of Sydney's calendar archive which contains all of the subject exams and other historical details.
Petr and I filmed a video for his channel at the same time, check it out here: ruclips.net/video/z1YhlaYQBeM/видео.html
Next time you could react to " Pisa normal school" entry test. It's the university where enrico fermi studied, i would love to see that :)
Is there an answer key?
And there...lies the beginning of the enlightenment process
Is it possible to talk to you about minoring or not in physics (current computer science student in undergrad). I'm starting to have way less interests in computer science directly. More interested in image processing, artificial intelligence, physics simulation, computational physics. Minoring or not or double another bachelor..
As always its a real treat to watch these kind of videos ( students with their smiles 😀).
You get a time machine. Expectation: I'm gonna go to the past and be a genius with my current science knowledge; Reality: You fail their exams.
so true! I expected serious answers.
That was whry Einstein failed lmao
@@dualia-s74m that's why? maybe, explaining PE emission in exams
Steven Mendoza The “Einstein failed math as a kid” myth is just that. He had actually mastered differential and integral calculus by the time he was 15.
@@colins6505 he failed in langauage
I liked that student's explanation of magnets using electron spin. Only J.J. Thompson didn't even discover the electron until 1897!
Everyone: what tf is that even supposed to mean
That one nerdier nerd: so the intersting thing about 1888 is that
yea thatt dude's pretty cool ngl
@@ahamuffin4747 bruhhhh, thats a no-no xDD
@@ahamuffin4747 say what
I loved that lol
@@ahamuffin4747 yeah, it was taken between 1901 an 1904 by a german scholar studying foreign culture. in western world, a photo was serious business, it was like getting a portrait painted. but i was new in china so the chinese farmer had never been exposed to such thing. and so he did an unconventional pose for western standart.
Next up, 2020 phistics students take a physics exam from 2132:
1) Define the universe, give three examples.
The almost complete absence of abstract questions and problems is very interesting. Almost everything is practical and somehow related to everyday situations
You mean very basic.
@Daniel Gomez I don't think they're basic in the modern sense. What I'm alluding to is James Flynn's theory that over the 20th and 21st centuries the approach to knowledge and intelligence has increasingly shifted from purely practical and concrete to universal and abstract.
@@Krawurxus I guess we should all be nomadic wanderers then
Can you elaborate how that has anything to do with a changing approach to education and intelligence?
@@Krawurxus Well, I'm not going to do the thinking for you. Knowledge about the nomadic lifestyle might be too universal and abstract for you. Stick to practical knowledge that's useful for your everyday life, like how to turn on the microwave to heat your pizza or how to operate the cash register. Don't think too hard, Darling. Stick to the practical. I'm sorry for challenging your beliefs. That was a step too far and too abstract for your mind
Up next: Physics students from 1888 react to 2019 exam
EDIT: Thanks for the 5.1K likes. That's about 69% of the total likes the video has.
Probably by attempting to perform experiments on your time machine to be fair.
Who wants to woooooosh him?
*WITCHCRAFT*
I have a Thyme Machine - it lets me get cooking herbs from the future when I run out ...
@James G dammit I've never wooshed anyway... but it was requested and now I feel obligated... r/whoooosh~~
On the question of photography by gaslight: It's not the amount of light, but the color of the light. The silver compounds used for black & white photography are relatively insensitive at the red end of the spectrum - which is why darkroom safelights were traditionally dim red lights. The color temperature of gaslight is around 2900K, which is quite red. So even with lots of lamps to give very bright gaslight, you'd have a hard time taking pictures in 1888. In the 1970s when sodium vapor street lamps were introduced, it was discovered that the light produced - just two spectral lines in the yellow range - was completely invisible to b&w film and paper, and new safelights were produced that made darkrooms as bright as any other room.
Thanks for the comment
good point! The amount of light was always an issue, but by 1880's emulsion sensitivity was getting pretty fast, Eadweard Muybridge was already doing his 'moving' series with something like 25 separate shots per second.
edit... I presume this was a specially made emulsion at the time, not in common use, as portraits would be shot on larger format with greater detail, so still slow exposures by today's standard.
Mate that's amazing - thanks for letting me know! I really need to go down this rabbit hole more!
Also note that the yellow street lights are actually good for the night sky but the new blueish LED ones are not good. But nobody cares about light pollution.
@@sciencepetr5179 old dark rooms (1970's) had 'safe lights' which were red. (or orange). My understanding at the time was that the red photons lacked the energy needed to trigger the chemical reaction.
en.m.wikipedia.org/wiki/Safelight
Somebody: Take a seat and relax
Me: What seat
Somebody: The seat of the electrical energy of a charged conductor
😂
@@suicidaleuphoria7012 They mean the electrical field and the magnetic field. The motional energy of a charge creates a magnetic field (it is like the kinetic energy in gravitation) which is outside of the conductor. If you calculate the amount of energy contained in the field you'd realise that the seat of the energy of a charge is in the dielectric around a cable. It is barely taught in modern school. Field physics in electric theory sadly has been falling backwards in my opinion.
That doesn't sound like a very relaxing seat ... Faraday's version of an electric chair, maybe?
@@suicidaleuphoria7012 I suspect it refers to the energy stored in the dielectric due to the charge on the conductor polarising the atoms/molecules in the dielectric, thus giving rise to the Polarisation vector.
Consider a parallel plate capacitor, with the capacitance given by C = Eo × Er × A ÷ d, where Eo (epsilon subscript zero) is the permittivity of free space, Er (epsilon subscript r) is the relative permittivity of the dielectric, A is the area of the conductor (subtended on the other conductor forming the capacitor), and d is the distance between the conductors. Vacuum has Er = 1, air has Er ≈ 1 (almost but not quite), whereas a dielectric such as rubber has Er = 7. So, a capacitor having a given conductor area and separation using rubber as the dielectric will have seven times the capacitance as that using air dielectric (for the same physical configuration).
The energy U Joules stored in a capacitor of C Farads charged to V Volts is given by U = ½ C V². Therefore, for a given voltage and same conductor area and separation, the capacitor with the rubber dielectric will store seven times more energy than the capacitor with the air dielectric. Ergo, one can conclude that the energy is stored in the dielectric.
Edit: added mathematical notation courtesy of my Android phone.
@@suicidaleuphoria7012 Yes, they knew about it - by 1888 Maxwell had published his theory on electromagnetism, and Heinrich Hertz was proving the theory by transmitting radio waves across his laboratory!
It was so fun to be a part of this video! Thanks for popping by USyd Toby :)
You are incredibly intelligent, and great at getting your point across. You're going to have an incredible career. All the best for the future!
im still trying to figure what accent you have. it certainly doesnt sound austrailian. im getting some canada vibes, perhaps in the west? like alberta?
@@Dizzula Thanks man - that's very sweet. I can't wait to finish this PhD and make beautiful things for the good people to enjoy.
@@ChrisChoi123 I'm sorry I don't make it easy - Russian who learned English from American TV - Seinfeld and Mythbusters mainly.
You were so coherent and smart with your ideas. I liked how you presented your ideas most compared to others.
Imagine if the 1888 exam reacted to the physics students
That would be freaky
how high are you
DarcnessTrophies 😂
@@DT_Worlds_Strongest_Goth no, it's "hi how are you"
They dead
They are dead by now maybe 1980s will work
1888 Teacher: What is gravity?
Me: It's the curvature of space-time caused by the energy that it contains and whose geometric deformation is defined by the equations of Einstein
Teacher: WAT? Space-time? Who is Einstein? Get out of my class!
Me: Guess you guys are not ready for that yet, but your kids gonna love it
I would love to see this extended with in-depth descriptions on each answer and how the answers have changed in over a century.
In general that is called a physics degree. :D
So much of what undergrads know now was unknown even to the brilliant minds back then. I wonder what might be common knowledge for undergrads 130 years from now that we don't even have a hint of.
ekdum sahi, but may be the leap physics made in past 2-3-4 hundred years is reaching saturation, it aint growing fundamentally at the rate, it grew in past centuries. other fields are now hitting puberty...
@@shivamb-s8k I understand what you imply but isn't it also true that the more you find out, the harder it gets to move on to the next level because of the complexity demanded?
@Johnston Steiner Obviously
I hope we'll have solved the dark matter and dark energy stuff, and have quantum gravitation figured out (or an even bigger theory that contains it).
And I wonder if the hints we recently got about what could be a 5th fundamental force are going to bring much to the table
I think even looking outside of undergrad levels of schooling. back in primary school (1995 or thereabouts) we were learning about film exposure on photosensitive paper via sunlight and silhouettes. Things that were once in the realm of advanced science have slowly trickled down into 'regular' science and finally into the public domain as assumed knowledge taught as early in life as 10-14 years old
1:43 by "seat of energy" the question means "storage location of energy"
It means to ask us to prove that the Electrical energy of a charged conductor stores in dielectric but not in the conductor. For example, the charged capacitor stores the potential energy not in the conductor of which its walls are made up of but it gets stored in the dielectric medium of the capacitor.
🙏
*In 200 years*
Reacting to a 2019 physics exam:
Oh yeah they thought time was onedimensional and who is Einstein?
Well we still know Keplar and Newton and Hooke and others, so there's a good chance that Einstein would still be remembered even if physics advances significantly in the next 200 years.
Lezhi Lo He definitely will be remembered for his work on relativity. He’s changed how scientists looked at the universe in 1905
History may forget historical figures. But science can't forget scientists.
@@cipherxen2 PepeScoots STOP
@@lezhilo772 Well I think he was joking.
The guy with the black shirt gives me a spider man 3 Tobey Maguire vibe
He reminds me of the clingy gay brother in wedding crashers lol.
Tobey was soooo yesterday I cant remember what he looks like, but thanks to the internetz... yea the vibe is there. Now! it'll be interesting if we could somehow measure this "vibes". 🦄
3019: toddlers reviews 2019 quantum theory
Actually I'm very intrigued by this exam, a lot of it is actually applicable to today's physics:
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1. What is the law of gravitation and the proof it is considered to rest - the law that 2 bodies attract one another at a force proportional to the square of the distance between the two bodies: earth and the moon, apple and the surface of earth. (1888 Newtonian Mechanics - can still be applied today for mathematical purposes and is still taught in University Physics today!!)
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2. Faraday and "the seat of electrical energy" question: Is probably a classical example how physics is "warped" by the English language. A quick google and I find that this is a terminology for, ..."reactions at each of the two electrode-electrolyte interfaces provide the "seat of emf" for the voltaic cell". One can write about oxidation and reduction reaction, with the EMF difference leading to voltage generated. Even today we have crazy issues related to physics and language, as an example there is no difference between scalar and vector in Portuguese, yet in the English physics course we dedicate so much time to what is really a language related intellectual concept.
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3. The photographic camera - I'm a little surprised that these students didn't jump at the concept of how light inverts through a pin hole camera and that a gas light source is too weak for this phenomena (although the second student go it right). Also check out my theory as to why people never smiled in photos or paintings below (please note I could be wrong).
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4. a google search and I found that ' Graduated Steelyard' was the name for a 'balance scale'. (why did we change the name?) They appear to be alluding to the formula of 'moments (force x perpendicular distance) - I couldn't read the remainder of the question. But this is a cool physics question, it was ruined by the changes in English. Just imagine how kids in the future will be reading our present day physics questions and asking, "what the hell is a Van Der Graaf Generator?"
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5. What is a magnet and how can you make a magnet? - Using 1888 physics (still applicable today). A magnet is a metal with all the 'magnetic moment' of the microscopic particles aligned. You can make one (at least temporarily) by placing a metal rod in an electric coil and electrifying the coil, this will align the 'magnetic moments' and create a magnet. As I said - still correct today.
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6. The Bell telephone - this is an essay type answer. Based on the principle of voice/sound beating on a surface (microphone) connected to a magnet vibrating inside a coil creating an alternating electric voltage moving in conjunction with the voice/sound down a line and in turn running back through a coil giving magnetic impulses to a magnet connected to a surface (speaker) and turning the human voice into electricity, running down a line and turning back into sound through a speaker. This principle was kept right through to about the 1990' s records, microphones and amplifiers, etc. Again - I kind of hoped these students would get this one. When the young scientists replied with, "I've never even seen a telephone."... my thought was first, "F#$k you, I'm not that old!". My second thought was, no hold on a second - you can still figure this dammit, I think you getting a fail mark.
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7. Okay Nicholson's hydrometer - a quick google and it's a buoyancy test gauge for different fluids. Okay quick one here: - I was actually impressed with reading about this as I use something similar to test oil based inks at my work. As a quick note you have a gizmo that is semi-buoyant with a vertical stick and markings for you to test its buoyancy in water. Mark the stick(where it penetrates the water level) then place it in another fluid and check the buoyancy level relative to water.... AND relative to the temperature. It's actually quite a cool physics test with math models etc, related to viscosity, buoyancy and temperature. Very applicable today and we could do the math and test accurately viscosity of fluids using the 1888 Nicholson hydrometer.
Great explanations
but where is your theory about people not smiling
dude..chill
XD
Thanks for the explanations.
Mark Plain I’m afraid your explanation for number 3 is incorrect. It has to with the colour of the light, not the amount.
Just a sidenote. I'm a Portuguese native speaker and there is a difference between vector and scalar in Portuguese.
As a graduate in ancient Greek, it has often been impressed upon me how the thought processes of former generations were colored by the beliefs, technology and even the vocabulary of their time. It is an error for us to feel certain that we know what they were talking about just because we can read their words or see images (as in old photographs or even ancient art) from their times. We do not have their context to necessarily decode their thought. Context must come before interpretation.
I thought a steelyard was a *place,* like a lumberyard or a schoolyard.
When the student taking the exam knows more than the examiner........
"CHECKMATE"
*checkmate liberal*
Yeah, except that girl doesn't know what a gas light or a steelyard is, for some reason.
And the one guy hasn't seen a telephone in his life. WTF?
Never used...okay. But never seen?
Somehow I also suspect his definition of telephone is a bit off, because they are everywhere around me.
Wouldn't it be wonderful if we actually get to see what the students answered to these questions back in 1880s. Are those records even present in archive?
So it seems old pyshics was more similar to modern engineering than to modern physics :)
really? How is that? I know that there is a very noticeable difference in the old exams and modern exams. Is perhaps how the questions were phrased that holds similarity?
@@iiopas9739 I think he's referring to stuff like "how would you build a telephone?" Which is something you'd probably ask an electrical engineer rather than a physicist.
@celine loves loona 이달소 they have an idea but don't dive into specific. For example, the telephone question would be a theory in physics. While the engineering student would give you the length of the wire, wire width, wire type etc.
@@StevenSmith68828 nice explanation
"I'm not actually an expert in early photography."
You sure as fuck sound like it tho bro, damn
All the physics exam I have ever taken in my life focused on mathematics and problem-solving. It seems that physics exams in the 19th century focused more on real-world problems than they do today.
I thought this was an exam for PHYS 1888, I was like dang that's a high level class!
"Magnet = lots of small magnets."
I'm not happy with that answer :(
It's turtles … all the way down😯
@@peterbrough2461 I knew it
You can think of electron spin, in a way, as little electromagnets.
Electromagnets work because charged particles in wires going in circles create a magnetic field. Electrons spinning on their own axis, then, also create magnetic fields.
Someone in 1888 might get all the stuff I said here apart from the stuff about electrons.
Idk man after solving the Ising model phase transition for half a semester I'm pretty happy with "Magnet = lots of small magnets".
Magnetism is a relativistic consequence of how electric fields are perceived, when the charges causing those field move.
Remember, changes in the electric field can only travel at the speed of light. When charges have no relative velocity to you, the electric field travels the way you would expect. If two charges are the same distance away from you, the waves in their electric fields will reach you at the same time.
However, once the charges are moving relative to you, the waves through the electric field won't reach you at the same time anymore. This relativistic "skewing" is what causes the magnetic force.
I'm afraid I don't know enough to explain it more deeply, but hopefully it gives you some idea. You can always google around if you want to learn more now that you know what to look for.
Feynman would’ve loved this exam for all the intuition
Those 3 students...I am one of those...subtly getting away with the answering part by cracking jokes and laughing 😂😂😂
5:00 People in 1888 did know that magnetic fields come from moving charge. They didn't know what atoms looked like though or what electrons were. Maybe they'd just say certain metals constantly experience moving charges (which isn't wrong)?
5:00 And that's why if you fire up a magnet in a furnace it loses its magnetic properties. Also why some metals get residual magnetism when exposed to magnets.
It's actually a lot of factors. 1. Amount of unpaired electrons in the outer shell. 2. The crystaline lattice structure of the metal. 3 Whether or not the "Domains" of the metal are also aligned.
Number 2 is why neodymium magnets are so strong even though neodymium is nonmagnetic.
Turns out that trying to find out why Gadolinium isn't the strongest magnet, leads you down a rabbit hole of knowledge.
The reason for the photograph thing is that they were using Silver Halide in those photographic plates. More importantly, it was before the discovery of the dyes that we used to make silver halide sensitive to light other than basically blue light. Gaslamps didn't give off enough blue light to actually take a picture using silver halide plates, both because of the spectrum of light given off by gaslamps was skewed towards the red end of the spectrum and because the amount of light given off was inadequate.
Seat = resting place.
Dielectric stops and holds charge. That's that.
Gaslight = light due to gas lamps or like gas street lights
I was a little surprised the girl had such trouble with the non-technical terms like "steelyard" and "gaslight".
I want to see the: 2129 physics students react to a 2019 exam
Why specifically 2129?
I just love the aesthetic of your videos. The framing of the video with the gorgeous bookcase, portrait, physics paraphernalia is the background is just perfect. It's calming, pleasing, and puts me a mood to get excited about scientific pursuits.
3:35 the sensitivity of old film/emulsions was only one part as to why people would not smile during photographs. In daylight or a well lit studio, there would have been more than enough light to take a adequately fast exposures, even in the 1870s. The more universal reason that we do not see people smiling in photographs is that getting a picture taken in early days was a very serious, expensive, and formal affair. Given this and the cultural understanding of what a picture was at the time, Westerners would have been considered idiotic to smile.
In early Eastern photography, btw you can find plenty of Asian men smiling.
Thank you for making this comment-good that at least some people are willing and able to correct the misconception.
I like those questions, because they test your understanding of concepts rather than your ability to memorise and juggle with equations without having a real understanding of what's going on.
3:35 another reason was because they didn't view a picture as much different from a painting which was a formal or serious afair. Not something to do flippantly like we do today.
Q.9 was interesting for me as a professional photographer. I've no idea what the expected answer is/was, but in 1888, emulsions were not panchromatic, meaning they were not sensitive to the whole visible spectrum, and were so insensitive to longer wavelengths of light that they could actually be developed under red safelight conditions like black and white wet process paper still is. As gas light's spectrum is limited to the longer end of the spectrum and contains almost nothing in the blue/green end of the spectrum, exposures under such conditions in 1888 would have been phenomenally long. Also, emulsions in general were very slow, so even with full spectral sensitivity, they'd still be tragically long. Its interesting to note that in 1888, when this paper was written, Kodak were just launching the ground breaking Kodak #1 camera which revolutionised photography as we know it. The reality is, the authors of this paper were probably unaware of this. Even so, in 1888, photo emulsion sensitivity was such that even in bright daylight, exposure times were such that most movement could not be captured. If only the authors knew that within 4 years of this exam paper being written, Q9 at least, would be mostly obsolete, and completely obsolete within 15. So fast was the progress in this arena at the turn of the 20th century.
Thank you for the photo at the end. I am working on a history of Broadway and this photo confirms there was once a substantial natural creek feeding the lake due to the size of the bridge at that time, and presumably the natural contour of the slope before major earthworks in the 20th century. In 1864 it would have been before the cutting was made extending Parramatta Road around the north side of the university, and Parramatta Road would have joined City Road to the south of the uni. City Road also had a different alignment then. It joined Broadway in the same place it does now but from about the Seymour Center it continued directly south and was much further east than the alignment it currently has. The old alignment is where Darlington Road and the part of Maze Crescent that goes from Darlington down to the back of the Seymour Center are now.
I see from the photo clear sky through the entrance arch which means that the west wing had not been built yet and there was no quadrangle to enjoy.
There is a lot more than just the physics examination questions that has changed.
It would have been interesting to read some of the answers that were marked correct at the time.
I can’t tell if the guy at 0:15 has an American or an Australian accent, or some mix of both.
I love this kind of reaction // showup exam review. Keep doing it please :)
Gas light would be mostly long waves of light far apart from each other... Similar to the red light of the dark room. The longer waves would not register on the negative. Instead the bright flash is mostly blue light which consist of shot waves closer together. These register better on the negative.
I'm rushing with the explenation of the gas light question.
Yesterday I've attendend the "wet plate"/ collodian photography course. The light-sensitive substance isn't picking up red light at all (thats why you can chemicaly process light-senistive image before stoping the reaction under red lamps) and is highly sensitive on blue spectrum of the light (f.eg. blue eyes apear to be brighter). Gaslight is not to dimm, it would just require longer exposure. It is probably emiting red-ish spectrum of light which is undetected by the silver compound of the liquid on your glass plate.
I urge you to check this tottaly owesome technique on RUclips. Just look for "wet plate photography".
Cheers! :D
The gaslight question is probably due to reciprocity failure in the emulsion.
EDIT: Or, as others have pointed out, lack of sensitivity to the red end of the spectrum.
I always appreciate physics tests you can't math your way out of.
My main disappointment with the video is that it was not followed up with the answer key (and commentary thereon).
Please do more videos like this. It is extremely interesting
When I realized that "gaslight" is referring to the light source that were lit by gas. The camera aside, Electricity light ain't even common back then.
Love how at 3:13 Petr explains image capture, then the camera operator adjusts exposure, like he's been just reminded, how that thing works :D
This was awesome, thanks for this!
Cool video! Thanks for making this.
6. I think this is in reference to electricity only flowing on the surface of conductors, or rather charge accumulating mostly on the surface. That is to say, the charge "sits" on the air contacting the conductor (dielectric).
Photographic film/plates of the era had limited spectral sensitivity (mostly blue and UV) and were basically “blind” to the spectrum of light emitted by “gaslight”
I missed you so much:-(
Where were you these days?
Hoping to upload much more regularly! Just got a bit busy and overwhelmed
@@tibees Aw, hope you're feeling better now! Don't feel bad taking time off! we'll always wait!
2089: We're going to give you an exam from 2019 to show you how silly it was.
This just shows how for over a hundred years our school systems uses the same things and way developed during that time and nothing has ever changed. The system developed during the time that worked producing liable workers and has carried on to today. I can write for hours but we need to change our system for our kids and our future if we want to stay in this planet for generations.
Oh you are completely right sir. There is nothing wrong with answering questions but what I am trying to say and should have qualified it more was that the way we treat this tests. How much we value over this exams. The amount stress it causes, problems, depression etc. How we use this tests to see about students and judge them in it. Or not. I am not trying to be the hater here but there is something odd about it. 😁
Had the electron been discovered then?
My grandfather, who worked for IBM during the Apollo Program, was excited when I told him that I knew how to use a slide rule. He was less excited when I told him I learned it in a college elective called "History of Math".
You deserve more subscribers❤❗❗
I love history and the way people wrote in the 19th century. I read a lot of US history, especially intellectual history, so I get some of this.
When they say the "seat of the electrical charge," seat means the basis or source of the electrical charge. The rationale for the word choice is that a "seat" is where something sits, where it is located or rightly located. This is seen in phrases like "the seat of power." The modern word choice would be something like "root," the source of nutrition and vitality for a plant.
As we learned more, the universe became even more confusing
Liked the video - was fun! Thank you!
3:44 I'm going to give you my theory as to why people didn't smile in photos nor in paintings: They may well have had skew teeth. I think this is one of the simple issues we overlook about time's gone by (before braces).... but I could be wrong.
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The painting entitled "Girl with a Pearl Earring" by Vermeer is extremely famous, I believe, because it is probably the only painting in its era to actually show teeth.
Wow, that was an awesome video concept. Sorry that it was too short :(
100 years later in 2120
They will also be laughing at ours
2120 undergradulates: Remember when we first learned that the interpretation of quantum mechanics was so stupid and how Einstein's theory was so limiting?
I actually don't think that's the case. Terminology might change a tad and the cultural reference points might shift a bit, but nowadays the stuff we learn at this level is pretty well-understood in a way that wasn't back then.
@@NotaWalrus1 We know more because we have more empirical evidence, but only now did people dliscover evidence for the universe not being flat, and quantum mechanics contradicts Einstein's theory of relativity, and simple things like how bicycle self-right and how planes fly aren't fully explained by science yet. Don't forget that other fields are still not yet to be fully explored like AI or the human mind
@@laffy7204 Which aren't topics studied at this level.
@@NotaWalrus1 At what level do you mean? If you're talking about how many subjects in science and technology aren't thoroughly explored 100 percent, then pretty much all of them do. There's plenty to discover in this vast universe. Sometimes we can combine things we already know into things we don't have before, like in material science for example
metals or other kinds of materials? what other kinds??
I would make a magnet by oxidizing iron such that for every 2 iron atoms there are 4 oxygen atoms
Thanks for the awesome video
My degree was in 1970. Long enough ago to know about gaslight and steelyards. I would have done OK.
Old photographic chemicals were intended to be used with light way above 5000K. Daylight at 10000K or burning magnesium worked best.
If the cameras back then *were* using some sort of silver colloidal... would gas lights have given off enough light in the blue spectrum to allow an image?
An 1888 student reacting to 2019 exam? Anything goes really...but an 1888 professor reacting to a 2019 exam? First words to leave their mouth "This is PREPOSTEROUS!!"😂😂😂
this is ABSURD!
@@ChrisChoi123 This is √(AB) !
Class of 2119 takes physics exam from 2020. Makes similar noises of confusion on the wording and difficulty of formed questions.
well, the dielectric have dipoles which change orientation in the presence of an electrical field. you could therefore call it 'the seat'
I wish they’d read the correct answers as well
Imagine you're a student in 1888 and you are shown a modern exam, with a brief outline of modern theories, but without any of the modern technology to test any of it. You know it's all true, yet it would completely screw you up, undermine everything you knew, all your current thinking... nothing would ever be the same again. How do you prove something if you haven't done the 100 years of ground work that was needed to get there? They'd throw you out of University and possibly lock you up for your own good! 😫
edit - that would be an interesting video: What modern Physics or Math theories could have been discovered / calculated in 1888 with only the knowledge and equipment that existed then? 🤔
I wonder where we will be in another 100 years
@@tibees probably looking back at 2019 exams and saying things like 'I've never seen a 'mobile phone', I think my grandad used to have one, they're funny, you had carry a box and touch a screen to talk to someone!" 😁
John Doe we’ll be apart of an ai consciousness and be immortal.
@@JohnDoe-tx8lq yeah after the floods those phones became bricks and were worthless.
the dude in the black shirt is on another level
Would really be interested in seeing one of the answer papers if they are still around. Wonder if they can be dug up from somewhere as well...
Physics exam: 1888
Niels Bohr norm: 1885
The magnetism/'spin' answer is complicated not just because quantum mechanics hadn't been formulated, but also because J.J. Thomson's concept/discovery of the electron wasn't until 1897, so you couldn't even use 'electron alignment' as an explanation.
Looking forward for the next episode: Phsysics students from 2150 react to 2019 exam.
It’s very interesting reading through the details and names in the calendar. It’s like a factual time capsule. I wonder what became of the students; especially those that received awards and scholarships.
"You need a lot of light to expose it properly" *video's exposure intensifies*
I am a commerce student watching a Video of Physics Paper from 1888 on a Physics channel. Why? I don't know.
"you need a lot of light to expose it properly"
*Camera man turns up exposure*
I wish I was smart enough to be a physics student :(
That reminds me of a reference I used in my undergraduate Metallurgy thesis that is so old it refers to work 'done by Chinamen'.
Dad : so laddy, whatya want for christmas :D?
Son : Nicholson's Hydrometer.
Everyone in the comments is talking about future exams, while I'm here wanting to know what the 'correct' answers would have been back in 1888
Go through the exam and solve the problems and explain the context of what they're asking!
i read somewhere that the not smiling for the photo had more to do with it being a very formal event - you would go to have your picture taken.
Question 6 would have confounded me 5 years ago... but it's just asking, on what grounds statement, that the basis of electrical energy is within dielectric is true. And yeah, If you think electrical energy flows in wires... WRONG!
All the electrical energy is in the electrical fields that flow through the dielectric. That is to say the material between two conductors. Whether it be glass fiber between conductors in a printed circuit board or in the air between two conductors (the live and neutral for example) in your walls.
;)
Yeah in a 100 years students will laugh at us! Hello students from 2120! Don’t laugh too much at us.
I feel bad for these students being in physics. I too made the same mistake.
What
*too
You are a mistake
It would be great to also show what would have been the "right" answers at the time. What would physics students have answered with the knowledge back then?
I actually want them to react to what the answers would have been now.
Lol just wait until next century... history shall repeat itself😂