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

  • @candleinthewind9135
    @candleinthewind91358 жыл бұрын

    I can't believe nobody's commented on how awesome his accent is yet.

  • @robertfinkle9020

    @robertfinkle9020

    8 жыл бұрын

    +candleinthewind "something to add about the CURRENT!"

  • @cowardlyheroine

    @cowardlyheroine

    8 жыл бұрын

    +candleinthewind He sounds a bit like Baymax? I'm only saying this because I watched Big Hero 6 recently :)

  • @yesiamadorito

    @yesiamadorito

    7 жыл бұрын

    OMFG IT WASN'T JUST ME

  • @ToDie4r

    @ToDie4r

    7 жыл бұрын

    true, it plays big role in making us understand better

  • @parksliderbarricade4324

    @parksliderbarricade4324

    7 жыл бұрын

    He reminds me of my Further Maths teacher. He's so enthusiastic and it's beautiful.

  • @johnmontgomery560
    @johnmontgomery5609 жыл бұрын

    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

  • @sandorclegane2485
    @sandorclegane24859 жыл бұрын

    I've never heard a clock that goes "mooo". Fascinating.

  • @yaseenahammed6352

    @yaseenahammed6352

    9 жыл бұрын

    Sandor Clegane I will eat every chicken in this room.

  • @finlaykingdon2063

    @finlaykingdon2063

    3 жыл бұрын

    hes British dont be racist

  • @missabcgirl123
    @missabcgirl12310 жыл бұрын

    learnt more in 36 minutes then i have in the entire year

  • @Benjones96

    @Benjones96

    10 жыл бұрын

    Glad im not the only one xD

  • @DrPhysicsA

    @DrPhysicsA

    10 жыл бұрын

    I hope it has proved helpful in any exams you may have been taking.

  • @krcd-eb6kb

    @krcd-eb6kb

    7 жыл бұрын

    Beth Jackson agreed

  • @ToDie4r

    @ToDie4r

    7 жыл бұрын

    exactly :)

  • @nataliaperez9372

    @nataliaperez9372

    5 жыл бұрын

    me right now

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    Thanks for your kind words. Glad they have been on some help.

  • @annepioquinto4784
    @annepioquinto47848 жыл бұрын

    Exam is tomorrow and I'm ready to go! Thank you immensely for making such digestible videos!

  • @DrPhysicsA

    @DrPhysicsA

    8 жыл бұрын

    Thanks. Hope the exam went well.

  • @TheRealWorld-TateSpeach

    @TheRealWorld-TateSpeach

    6 жыл бұрын

    What did you get?

  • @johnpaul4301

    @johnpaul4301

    5 жыл бұрын

    @@TheRealWorld-TateSpeach he failed with flying colors

  • @hadeedahmad9465

    @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

    @snhtsljedc9803

    3 жыл бұрын

    Hadeed Ahmad do u still need an answer?

  • @ARaven5
    @ARaven510 жыл бұрын

    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

    @DrPhysicsA

    10 жыл бұрын

    Thanks. And all good wishes for the exam.

  • @deebarfield2633
    @deebarfield263311 жыл бұрын

    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 :-)

  • @walshamite
    @walshamite11 жыл бұрын

    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!

  • @heidigarbett97
    @heidigarbett9710 жыл бұрын

    youve genuinely made everything ive been taught in class become clear to me now

  • @MathPhysicsFunwithGus
    @MathPhysicsFunwithGus4 жыл бұрын

    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!

  • @NTye
    @NTye11 жыл бұрын

    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!

  • @pico5746
    @pico57467 жыл бұрын

    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

    @DrPhysicsA

    7 жыл бұрын

    All good wishes with your studies.

  • @bigrockets
    @bigrockets4 жыл бұрын

    most excellent presentation on waves, angles of incidence , refraction and reflections. Well done!!!

  • @alext9067
    @alext90677 жыл бұрын

    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

    @DrPhysicsA

    7 жыл бұрын

    Well spotted. Its a cuckoo clock with a cow instead of a cuckoo!

  • @phynos8936
    @phynos893610 жыл бұрын

    Wonderful video. Thank you.

  • @AmitMusicProductions
    @AmitMusicProductions10 жыл бұрын

    Sounds like the exam solutions guy..

  • @Jood9090
    @Jood90906 жыл бұрын

    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!

  • @asthav3000
    @asthav30008 жыл бұрын

    Thank you soo much for these videos!! I really appreciate it, you've helped me a lot!

  • @fatimaposwal7894
    @fatimaposwal78949 жыл бұрын

    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

  • @mdk124
    @mdk12410 жыл бұрын

    Really appreciate your effort going through all this! Not sure if i could have talked about physics for 30 over minutes!

  • @akshaypetta
    @akshaypetta11 жыл бұрын

    This is probably the best thing to happen to KZread. Thank You.

  • @els257
    @els25711 жыл бұрын

    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!

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    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.

  • @SkiGav
    @SkiGav11 жыл бұрын

    Mate, ur the absolute best! love your videos and i really really appreciate what you're doing for everyone out there!

  • @donaldcambridge1040
    @donaldcambridge104010 жыл бұрын

    life saver. awesome video man

  • @jorgegonzalez-ec5fl
    @jorgegonzalez-ec5fl7 жыл бұрын

    This guy really knows what he's talking about. I'm glad we still have real teachers out there.

  • @keithdawes2685
    @keithdawes26859 жыл бұрын

    Bloomin' Marvelous - Thank you.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @rachelbarn6011
    @rachelbarn60118 жыл бұрын

    You are God sent sir! Thank you so much for these videos

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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).

  • @cadkls
    @cadkls10 жыл бұрын

    You draw such beautiful waves.

  • @sandlertossone1813
    @sandlertossone18133 жыл бұрын

    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.

  • @fernandrasta4786
    @fernandrasta47868 жыл бұрын

    Your channel is fantastic, thx you so much ... I am watching them all

  • @niharikags6129
    @niharikags612911 жыл бұрын

    Very Well Explained!! You are very good teacher! You have made difficult concepts much easier to understand! Hats off! Thank you!

  • @marianthejuniorscientist6422
    @marianthejuniorscientist64226 жыл бұрын

    Really great resource for students as well as teacher ...

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    Many thanks. Hope it starts to make sense soon.

  • @davinapaul5328
    @davinapaul53288 жыл бұрын

    thank you so much for this video. you have no idea how much it helped me finally understand waves :)

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    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.

  • @Benjones96
    @Benjones9610 жыл бұрын

    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

    @DrPhysicsA

    10 жыл бұрын

    Hope the exam goes really well.

  • @parksliderbarricade4324
    @parksliderbarricade43247 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    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

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    Delighted to hear that. Keep going for that A!

  • @quantum3280
    @quantum32803 жыл бұрын

    Love watching these in 2020 quarantine

  • @anshuthapa524
    @anshuthapa52412 жыл бұрын

    wow, loving your videos! much thanks!

  • @shaahashareef8868
    @shaahashareef88689 жыл бұрын

    You are much better than any teacher in school. Thank you so much sir. You are awesome! 😊😄

  • @ucingtigatiga
    @ucingtigatiga12 жыл бұрын

    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 !

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    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.

  • @zehnsarwar
    @zehnsarwar11 жыл бұрын

    missed a lot of work you helped me catch up a lot. thanks

  • @pufalupagus
    @pufalupagus11 жыл бұрын

    Great job i'm 16 yrs old and i understand this perfectly. Watching your lectures is a great pass time of mine

  • @wateen914
    @wateen9147 жыл бұрын

    Thank you so much it was really helpful, took few hours to watch this video with countless pauses but it worth it.

  • @jessicawhitney2074
    @jessicawhitney20746 жыл бұрын

    I'm woefully unprepared for my resit tomorrow, this series of videos has helped a lot :) thank you for making these

  • @DrPhysicsA

    @DrPhysicsA

    6 жыл бұрын

    Jessica Whitney all good wishes for the exam

  • @Verbalbangz
    @Verbalbangz12 жыл бұрын

    By playing these over and over in my sleep i hope to remember it

  • @sanjayraoshedge8924
    @sanjayraoshedge89248 жыл бұрын

    Marvellous lecture , i have recaptured lost memory!!

  • @aki957
    @aki9579 жыл бұрын

    Thank you. Now has a better idea of what chapter wave is about.

  • @mrphysicus343
    @mrphysicus3439 жыл бұрын

    Thank you sir! Clear and wonderful explanation.

  • @umeshchandramakwana806
    @umeshchandramakwana8066 жыл бұрын

    Excellent accent and explainations !! Thank you for teaching very nicely!!

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @mohamedridamahir1960
    @mohamedridamahir19605 жыл бұрын

    thank you , mister this series is awesome and quite helpful in dutch education

  • @madamai123
    @madamai12311 жыл бұрын

    Thank you for all the videos you are uploading, i am finding them very helpful for my As physics course

  • @natashakulatunga3098
    @natashakulatunga30989 жыл бұрын

    this was great! i got evrything that you just said.... thanx soo much!

  • @mboulan96
    @mboulan9611 жыл бұрын

    Thank you so much! Really, really helpful - I'm finally starting to get this topic!! :)

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @kavya1379
    @kavya13799 жыл бұрын

    Thank you so much for this!! It was definitely a huge help

  • @AlexBoffey
    @AlexBoffey11 жыл бұрын

    Thankyou! Your videos have helped me with my exams this january, and im sure they will help further for my exams in june aswell!

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @khuzaimahsaqib692
    @khuzaimahsaqib6927 жыл бұрын

    thank you sir i have learnt much more in these 36 min

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    To you and all sitting the exam today, all good wishes.

  • @dalemcmahon123
    @dalemcmahon12312 жыл бұрын

    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 !!

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    Thanks. I have done a number of videos with example exam questions from the various A Level courses.

  • @kylefan7237
    @kylefan723710 жыл бұрын

    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! :)

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @0113slimshady
    @0113slimshady11 жыл бұрын

    Why don't I have a teacher like you! Thanks soo much! :)

  • @joeykyw6155
    @joeykyw615512 жыл бұрын

    Thank you DrPhysicsA. You explanations were really clear and precise. :)

  • @NHKitty234
    @NHKitty23411 жыл бұрын

    Thank You so much for this Video! It really helped me to clear my concepts regarding waves! :)

  • @flexddd
    @flexddd11 жыл бұрын

    exam in around a week for physics :D all your videos helped me so much tyvm

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    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.

  • @bryonycoombs1018
    @bryonycoombs101810 жыл бұрын

    BLESS YOU SIR I UNDERSTAND AND 2 DAYS BEFORE MY EXAM

  • @DrPhysicsA

    @DrPhysicsA

    10 жыл бұрын

    Thanks. Hope the exam goes really well.

  • @MrKraftyy

    @MrKraftyy

    10 жыл бұрын

    OCR Electrons waves and photons? lol

  • @longdragon3

    @longdragon3

    10 жыл бұрын

    MrKraftyy can't wait for it. lol

  • @MrKraftyy

    @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

  • @crazyPCbuilds
    @crazyPCbuilds12 жыл бұрын

    This video was so useful! thanks!

  • @StainlessScience
    @StainlessScience11 жыл бұрын

    This is all extremely helpful, thanks a lot.

  • @DrPhysicsA
    @DrPhysicsA11 жыл бұрын

    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.

  • @PrashanthAmbatimob
    @PrashanthAmbatimob11 жыл бұрын

    Amazing! online lessons just got better!

  • @DrPhysicsA
    @DrPhysicsA12 жыл бұрын

    Thanks. Glad the video was of some help. Good luck with the future exams.

  • @FrankyyProductions
    @FrankyyProductions12 жыл бұрын

    Very helpful, much easier to understand than the boring old textbook! :D Thank you!

  • @marymagpie1
    @marymagpie111 жыл бұрын

    Thank you for this!! It is such s great help!

  • @alphie10
    @alphie1012 жыл бұрын

    @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

  • @Aycgjk
    @Aycgjk11 жыл бұрын

    Doing an amazing job!

  • @dontharindu9544
    @dontharindu95449 жыл бұрын

    Thank u soo much DrPhysicsA Helped me alot .

  • @sfsoma
    @sfsoma12 жыл бұрын

    Thank you for the excellent lecture.

  • @spaceplanetarium
    @spaceplanetarium11 жыл бұрын

    This is brilliant, thank you so much

  • @Azeembakhsh1
    @Azeembakhsh17 жыл бұрын

    Best teacher ever !

  • @HappyBappyBeth
    @HappyBappyBeth11 жыл бұрын

    Thank you so much, your videos are so helpful!

  • @samlumley7592
    @samlumley759212 жыл бұрын

    You are the saviour of my A Level :D

  • @RedfernModelRailway
    @RedfernModelRailway8 жыл бұрын

    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!

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