Waves - A Level Physics
Ғылым және технология
Continuing the A Level revision series with Waves. Looking at transverse and longitudinal waves, the electromagnetic spectrum, polarisation, interference, the single slit and double slit experiments, a diffraction grating, refraction and refractive indices.
Пікірлер: 544
I can't believe nobody's commented on how awesome his accent is yet.
@robertfinkle9020
8 жыл бұрын
+candleinthewind "something to add about the CURRENT!"
@cowardlyheroine
8 жыл бұрын
+candleinthewind He sounds a bit like Baymax? I'm only saying this because I watched Big Hero 6 recently :)
@yesiamadorito
7 жыл бұрын
OMFG IT WASN'T JUST ME
@ToDie4r
7 жыл бұрын
true, it plays big role in making us understand better
@parksliderbarricade4324
7 жыл бұрын
He reminds me of my Further Maths teacher. He's so enthusiastic and it's beautiful.
I love your lectures. When I retired I was considering going back to university to study physics. Now I can do it at home with a superb lecturer John
I've never heard a clock that goes "mooo". Fascinating.
@yaseenahammed6352
9 жыл бұрын
Sandor Clegane I will eat every chicken in this room.
@finlaykingdon2063
3 жыл бұрын
hes British dont be racist
learnt more in 36 minutes then i have in the entire year
@Benjones96
10 жыл бұрын
Glad im not the only one xD
@DrPhysicsA
10 жыл бұрын
I hope it has proved helpful in any exams you may have been taking.
@krcd-eb6kb
7 жыл бұрын
Beth Jackson agreed
@ToDie4r
7 жыл бұрын
exactly :)
@nataliaperez9372
5 жыл бұрын
me right now
Thanks for your kind words. Glad they have been on some help.
Exam is tomorrow and I'm ready to go! Thank you immensely for making such digestible videos!
@DrPhysicsA
8 жыл бұрын
Thanks. Hope the exam went well.
@TheRealWorld-TateSpeach
6 жыл бұрын
What did you get?
@johnpaul4301
5 жыл бұрын
@@TheRealWorld-TateSpeach he failed with flying colors
@hadeedahmad9465
5 жыл бұрын
@@DrPhysicsA can you tell me how much this video covers the cie alevel waves topic? Does this leave anything out that is in the cie syllabus?
@snhtsljedc9803
3 жыл бұрын
Hadeed Ahmad do u still need an answer?
woah, my physics exam is next week and this has helped me a bunch! amazing video, thank you!! (much better than my teachers:P)
@DrPhysicsA
10 жыл бұрын
Thanks. And all good wishes for the exam.
Loving the fact there's so many people watching these videos as last minute revision! They're so informative and everything is explained really well! Thank you :-)
This series is GREAT. At school (1960s), did General Science, ), not enough physics there. Following hobby of astronomy-cosmology, I've been aware of gaps needing knowledge. Using YT physics clips to fill my gaps. Kinda knew some of it, but back to basics makes me see relationships as never before. I can follow the math. In my 60s now, still love steep learning curves. I learn better these days, no exams, just the joy of knowing. Thanks a 10 to the minus 6. It's a joy. UR never 2 old 2 learn!
youve genuinely made everything ive been taught in class become clear to me now
Your videos are amazing! I am first year undergraduate physics major and I proved that e&m waves travel at c after watching your videos and I understand the whole derivation and proof and can do it on my own no problem! Thank you!
This was brilliant, like having a revision lesson without being at school! But a lesson I can pause, rewind etc as often as I need to. I was really struggling with standing waves, but you've helped me, thanks a lot!
I've just started A-levels but I need to do really well so watching these early on should help with revision later on as i'll just need to recap
@DrPhysicsA
7 жыл бұрын
All good wishes with your studies.
most excellent presentation on waves, angles of incidence , refraction and reflections. Well done!!!
I like the clock mooing. I will also add that these videos are of tremendous interest to me and that I appreciate your effort and your candidness in presenting them.
@DrPhysicsA
7 жыл бұрын
Well spotted. Its a cuckoo clock with a cow instead of a cuckoo!
Wonderful video. Thank you.
Sounds like the exam solutions guy..
I like the way he explained!! I need this man guys!!!! he's explaining better than mt teacher, I feel that he's is understanding what he's saying not like the other only say what they know and he also explain slower. really I like this man!! and I need him also!
Thank you soo much for these videos!! I really appreciate it, you've helped me a lot!
Thank very much Sir! I respect teachers because they teach you what they love teaching and only those who have a passion to teach others teach to a good standard. May God guide you and be with you. Best wishes, physics student
Really appreciate your effort going through all this! Not sure if i could have talked about physics for 30 over minutes!
This is probably the best thing to happen to KZread. Thank You.
Thank you, I am an A* Student and I have been struggling a lot with this unit and this has really cleared a lot of things up for me. Thank you so much for your help!
Thanks for comment. I'm not really sure what the benefits of polarisation might be. Google suggests some. But polarised glasses will reduce the amount of light entering the eye and can also reduce reflected sunlight (glare) which is itself polarised.
Mate, ur the absolute best! love your videos and i really really appreciate what you're doing for everyone out there!
life saver. awesome video man
This guy really knows what he's talking about. I'm glad we still have real teachers out there.
Bloomin' Marvelous - Thank you.
You are quite right. Its a moot point whether that counts as internal reflection. But as you say, beyond the critical angle it certainly is internally reflected.
Lamda is defined as the wavelength - ie the distance between consecutive peaks in the wave. Frequency is defined by the number of wave peaks passing a point per second. The speed of the wave is the product of the two.
Sorry about that. What we are saying is that as light passes through a double slit it will form a pattern on the screen which is a series of alternating light and dark patches (a series of black and white stripes if you like). These are called fringes. We usually call each light stripe the fringe and the distance between any two fringes is the distance from the peak whiteness of one to the peak whiteness of the next.
You are God sent sir! Thank you so much for these videos
Thanks for kind comments. Quantum Mechanics is bizarre. We don't mean that particles travel as waves we mean that particles are waves. My advice for what it is worth, is that the best way of understanding quantum mechanics is not to try to equate it with anything in the classical world. Analogies can be helpful but are often misleading. Just accept that the quantum mechanics world is weird and counter-intuitive when compared with the classical world we inhabit.
I am magnifying the whole slit so it is of length d. The argument is that in the circumstances I describe, you can think of the slit as being of two halves (each of d/2). Light from any point in the top half will be exactly out of phase (ie will cancel out) light from the corresponding point in the lower half. So all the light from the top half cancels the light from the bottom half (at the angle theta).
You draw such beautiful waves.
Would love to hear a lecture on transmission line theory. Most video's online are not very helpful. I have watched almost all your videos and can say learned something new in each one. You have a special gift of taking complicated theory and relaying it simply to the everyday person.
Your channel is fantastic, thx you so much ... I am watching them all
Very Well Explained!! You are very good teacher! You have made difficult concepts much easier to understand! Hats off! Thank you!
Really great resource for students as well as teacher ...
sin r = 1 at the critical angle. This is the angle at which the angle of refraction is 90 degrees (ie along the surface of the water/glass). sin 90 =1. Beyond the critical angle, all the light is totally internally reflected.
Many thanks. Hope it starts to make sense soon.
thank you so much for this video. you have no idea how much it helped me finally understand waves :)
This can get very philosophical. The speed changes and there is a compensating change in wavelength such that c=λf, but f itself does not change. The energy of the photons do not change (since E=hf). But the key point is that in order for you to see the colour the light has to leave the medium (glass, water etc) to travel thro your eye to your retina. So the only real sense of colour is that which is determined by the wavelength and frequency of light in your eye as it hits the retina.
you have saved my life.. and for that i am eternally grateful... exam tomorrow and found these vids which have cleared up so much! thank you! :D
@DrPhysicsA
10 жыл бұрын
Hope the exam goes really well.
Just found this channel recently and this is perfect for getting a good grasp on Physics. Luckily, Physics is Linear so given I get a pass, I can use these videos to boost my grade greatly.
Much depends on where you draw the x axis. A trough isn't usually defined in that way. A trough is the point at which the wave reaches its lowest point on the y axis, just as a crest it where the wave reaches its highest point on the y axis. Eg y = sin x
At 21:00 I am showing a particular light wave which is at angle ϴ (ie the angle which will produce a dark patch on the screen). This means that at that angle, the light waves reaching that point on the screen are canceling each other out. Geometry relates ϴ, d and λ. So we show what the condition is for light waves to cancel out.
Delighted to hear that. Keep going for that A!
Love watching these in 2020 quarantine
wow, loving your videos! much thanks!
You are much better than any teacher in school. Thank you so much sir. You are awesome! 😊😄
i agree,DrPhysicsA have great method explaining physics,to the point theoretically yet still engage intuitively.please expand your teaching by give problems to solve mr DrPhysicsA !
The idea is that every point along the slit is a source of light so every point generates a light ray (the Huygens principle). I drew in the ones at the top and bottom of the slit and one in the middle. Then I show that every light ray in the top half exactly cancels the corresponding ray in the lower half.
missed a lot of work you helped me catch up a lot. thanks
Great job i'm 16 yrs old and i understand this perfectly. Watching your lectures is a great pass time of mine
Thank you so much it was really helpful, took few hours to watch this video with countless pauses but it worth it.
I'm woefully unprepared for my resit tomorrow, this series of videos has helped a lot :) thank you for making these
@DrPhysicsA
6 жыл бұрын
Jessica Whitney all good wishes for the exam
By playing these over and over in my sleep i hope to remember it
Marvellous lecture , i have recaptured lost memory!!
Thank you. Now has a better idea of what chapter wave is about.
Thank you sir! Clear and wonderful explanation.
Excellent accent and explainations !! Thank you for teaching very nicely!!
It covers material in the AQA, OCR and Edexcel syllabus and I have also added some material from the CIE syllabus. I cant guarantee that it covers everything. If anyone spots gaps, let me know and I'll try to add more videos to cover them.
thank you , mister this series is awesome and quite helpful in dutch education
Thank you for all the videos you are uploading, i am finding them very helpful for my As physics course
this was great! i got evrything that you just said.... thanx soo much!
Thank you so much! Really, really helpful - I'm finally starting to get this topic!! :)
They are permittivity of free space and permeability of free space respectively. I haven't done separate videos on them. For A Level it isn't necessary to know the detail of these constants.
Thank you so much for this!! It was definitely a huge help
Thankyou! Your videos have helped me with my exams this january, and im sure they will help further for my exams in june aswell!
Well frequency is one divided by the Period (T). T is measured in seconds. Frequency is measured in cycles per second. So frequency tells you how many cycles or wavelengths pass a particular point per second. T tells you how long it takes one wave to pass the given point.
thank you sir i have learnt much more in these 36 min
To you and all sitting the exam today, all good wishes.
Thanks again. It makes sense now!!! The photon has to pass through the eyeball to reach the retina. The eyeball is gelatinous and will further slow down the light and change the wavelength depending on the refractive index of the eye material so it doesn't matter on what type of medium that the photon has to travel through before it reached the eye. Thanks a lot for replying!...........I have got it ! eureka !!
Thanks. I have done a number of videos with example exam questions from the various A Level courses.
Wow, thank you so much for this video. It got the extra marks for me a great student from a good student. Could've scored a high B, but got carried into the A range with your video. Very informative and helpful! :)
Path difference is just a measure of how much out of phase one wave is with respect to another. It can be measured in terms of wavelengths. But the key point is the fraction of a wavelength by which one wave is out of sync. This can be expressed either in terms of wavelengths of radians (2 pi rads = 1 wavelength). Frequency doesn't really afffect path length. No matter what the frequency two waves can be out of phase.
Why don't I have a teacher like you! Thanks soo much! :)
Thank you DrPhysicsA. You explanations were really clear and precise. :)
Thank You so much for this Video! It really helped me to clear my concepts regarding waves! :)
exam in around a week for physics :D all your videos helped me so much tyvm
A good way to understand phase difference is to consider two waves with the same frequency, wavelength and amplitude which start out at different points. How far is the second wave behind the first one? You could give the answer in terms of distance - but that wouldn't tell us very much. We could give the answer in terms of wavelength. So if the second wave was half a wavelength behind then the two waves would be completely out of phase. Or you could regard each wavelength as 1 cycle = 2 pi rads
There are various ways photons interact with matter, but the key one for the issue you raise is that some photons give up all their energy as opposed to a partial loss of energy by all photons. For example a photon might transfer its energy (E-hf) to an electron and liberate the electron from the atom with an excess of Kinetic Energy that is eventually converted to heat energy. The photon beam would then be less intense but photons which had not interacted would retain their original energy.
BLESS YOU SIR I UNDERSTAND AND 2 DAYS BEFORE MY EXAM
@DrPhysicsA
10 жыл бұрын
Thanks. Hope the exam goes really well.
@MrKraftyy
10 жыл бұрын
OCR Electrons waves and photons? lol
@longdragon3
10 жыл бұрын
MrKraftyy can't wait for it. lol
@MrKraftyy
10 жыл бұрын
karan Naga lol i can wait, done it last yr and got a C. Ive been focusing on a2 so just started recaping yday lol
This video was so useful! thanks!
This is all extremely helpful, thanks a lot.
Yes you rightly make the point that photons travel at c only in vacuum (and more or less in air). But slower in denser media.
Amazing! online lessons just got better!
Thanks. Glad the video was of some help. Good luck with the future exams.
Very helpful, much easier to understand than the boring old textbook! :D Thank you!
Thank you for this!! It is such s great help!
@DrPhysicsA Brilliant videos!!! My mechanics exam went fabolous i made a few silly errors on some of them but hopefully iv got that magical A that i want haha! If it wasntfor your videos dont know what i would do you cover things sometimes that my teachers dont and it gives me a better all round knowledge fantastic stuff! Thank you!! Now i gotta watch ur videos and Study for the Electricity and Waves exam
Doing an amazing job!
Thank u soo much DrPhysicsA Helped me alot .
Thank you for the excellent lecture.
This is brilliant, thank you so much
Best teacher ever !
Thank you so much, your videos are so helpful!
You are the saviour of my A Level :D
Thanks for this. My physics teacher isn't the best (or i might be a bit slow still after the holiday :/ ) and you've helped to patch up some of the gaps he left me with!