Emission and Absorption Line Spectra – A Level Physics

Published on February 23, 2015 by

Why are fireworks coloured, how can we tell what elements are in stars just from the light we see? This video explains why physics is all about sunshine and rainbows.

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  • TMOTU 7 years ago

    Really good videos! Better than Dr PhysicsA

  • Emmanuel Oladokun 7 years ago

    So does that mean emission spectra is strictly when electrons move to a lower energy level and absorption spectra is strictly when electrons move to a higher energy level.

    • Physics Online 7 years ago

      You are right, the emission spectra is due to the emitted photons when electrons drop down, the absorption spectra is when the electrons move up.

  • Hammy🧡 7 years ago

    You’ve literally saved my life, great videos! Does this mean atoms absorb and emit the same frequency of photons?

    • Physics Online 7 years ago

      @hammyogunlayi Yes, their absorbtion and emission spectra are the same (but one is like the negative image of the other).

  • Hafiz Patwary 7 years ago

    Great videos. What I needed just 5 days before the exam :’)

  • Grape 7 years ago

    i literally get goosebumps when i watch ur videos XD

  • numan wazir 7 years ago

    when electron de excitation why it come again to lower orbit

    • ElvishJumpSuit - Physics Teacher 7 years ago

      +numan wazir They have to……..it’s the Law!!!  Excited states are generally short-lived and the system wants to go back to its lowest energy state.  Like the way weight pulls the centre of gravity to its lowest position.  Nature likes it that way 😉

    • BronzeJourney 5 years ago

      You cant run forever right?

  • VecZ 7 years ago

    Great explaination 😀

  • MoMax 6 years ago

    omg this took alot of contemplation thank you soo muchhh mann! i gottthiss i cant believe it! thankk youu soo much for getting out your way for us!

  • Ursa Mahan-Worlds 6 years ago


  • necrobreen 6 years ago

    OMG KING OF PHYSICS! thanks for this video. Exam’s in a week….

    • Physics Online 6 years ago

      +necrobreen Good luck

    • Didier Leopold 6 years ago

      does the black line on the emission spectra mean that the photon emit light in all directions.

  • Nom Chicky 6 years ago

    You’re such a lad

  • Mo Leily 6 years ago

    Thank you that very useful

  • HypedDragon 6 years ago

    5:30 am revision- exams in 3 and a half hours… quality videos mate, if only I had found them sooner

    • Physics Online 6 years ago

      At least you have them now for the Depth and also for all of the year 13 content.

    • HypedDragon 6 years ago

      +A Level Physics Online true, many thanks for the time you’ve took to explain the topics

    • Physics Online 6 years ago

      Good luck in your exam

  • Black Sideburns 6 years ago

    What happens if you have light that is higher energy than needed to promote to 2 but lower than needed to promote to 3? What happens??

    • Physics Online 6 years ago

      Nothing. Only if the exact amount of energy for an electron to change levels is provided will it move. There can’t be any left over.

  • Sanjay Sojan 6 years ago

    +A Level Physics Online. I love physics, I really do. If only I had you as my teacher so I could pass my exams. Thanks for the quality videos….

  • mukesh gandhi 6 years ago

    a levels physics nice with model

  • Reuben Hopper 6 years ago

    so when an electron absorbs energy and moves up a level, wouldn’t it also have to emit that level of energy as well because it’s unstable there and needs to drop down? this doesn’t make sense to me because that means that no matter what spectrum of light is absorbed, it must also release that spectrum of light. this doesn’t make sense because then if you shine white light at something and it absorbs a certain frequency, you will still see white light reflected back because whatever was absorbed has to me emitted. sorry that was a bit confusing…

    • Bugra Engin 5 years ago

      When white light passes through a material, some photons of specific frequency and of specific colour will be absorbed in the transition of an electron, whilst some photons will just pass through the material (these photons don’t have that particular frequency to excite an electron). This should explain why an exact continuous spectrum of white light would not be detected on the other side of the material.

  • Redbanana 6 years ago

    For some reason we’re learning this in Ireland as part of the Chemistry leaving Cert course 0.o

    • Physics Online 6 years ago

      It’s all good science!

  • Lukahn Apeirogon 6 years ago

    Ur too quick :'(

    • Seong Saw 5 years ago

      icecubeinferno read through lecture notes or course books, then watch his videos. you’ll understand better.

  • Gilo Tintin 6 years ago

    Got an EOT tomorrow about Quantum Physics and this just solved my confusion on Absorption Spectrums. The teachers have put up posters promoting your channel around college, absolutely class. Thank you!

    • Physics Online 6 years ago

      That is fantastic – message me with your college name and I can send some more through.

  • Max Wilson 6 years ago

    Very helpful, thank you

  • Viki awesome 6 years ago

    Each of your videos deserve at least 1 million views!! It’s that good!!!

    • Physics Online 6 years ago

      +Viki awesome Thanks (I wish it does get that big!)

  • liiahhh 6 years ago

    one of the best explanations i’ve seen! studying for my exam later today 🙂

  • Joshan Amalendran 5 years ago

    He says that absorption spectrums occur when passing light through a cold gas, so how can it be used on stars when they release so much thermal energy?

  • Daniel Debbarma 5 years ago

    do u have the explanations on Bohr’s second postulate of quantisation…?if yes plz reply me the link ..I have exam tomorrow..thank you

  • Haris Chastoukis 5 years ago

    Please allow your videos in greece i am in an international school religion is not fanatic here we accept sience and your videos help me a lot thank you for your hard work please allow astophisics for us 🙂

  • majeed shah 5 years ago

    Amazing! Keep it up, man!

  • Luke Jones 5 years ago

    Hi, I was wondering where you cover stimulated emission (I have the year 13 videos as well) as I cant seem to find it, cheers

  • mr biggie cheese 5 years ago

    I’m curious is everyone here in there A-levels or is there anyone younger like me ?

    • Physics Online 5 years ago

      Alex . Exe Most people are older, but that shouldn’t stop you. Keep watch my and you’ll find plenty of interest me material.

  • Squished macaroni 5 years ago

    I spent 3 weeks trying to understand this ……..
    Should have YouTube this up …Awesome work sir

  • Avisek SSarma 5 years ago

    awesome video..but i have a question,,why is only some part of a colour absorbed by elements but not all part of that specific colour? i mean when some part of green colour is absorbed, why not all green colour?

  • Mastercheif1345 5 years ago

    But if transitions to n=1 gives out UV, how come you say that it emits a rainbow of colours?

  • cress 5 years ago

    Great video!!!!! Thank you

  • Roshan Bhamra 5 years ago

    Clearly anti-flat earth propaganda. This should be called the Lieman series.

  • BronzeJourney 5 years ago

    I have one question i hope you answer, helium got 2 electron, but why there more than 2 line? Is this because we cant tell where the electrons actually are? Or the matter we observe contains many atoms and data also contains things from that atoms as well? Or what? Thank you so much for the video great explanation.

    • Physics Online 5 years ago

      BronzeJourney because even for just 1 electron there are many possible energy states it could exist in.

    • BronzeJourney 5 years ago

      Thank you and i have one more question if you dont mind, how scientist can say that galaxies going away from us by looking that spectrums, and which one they are using specificaly (I guess they are using absorbtion spectrum since stars are burning and contains gases that we can synthesize in lab, is that correct?) and why they are using that one? Thank you so much.

    • Physics Online 5 years ago

      It’s the stars atmosphere that absorbs some light at these particular frequencies, when we see the star light we see what remains – and its the redshift of these lines that tells us how fast they are moving away.

  • Jamie White 5 years ago

    Fantastic video thank you, this helped me with my A-Levels so much!

  • Aiysha Malik 4 years ago

    Emission of photon when an electron moves to a lower energy level and emission of photon during gamma decay is different?
    During gamma decay does electron move to a lower energy level?
    I would appreciate it if you answer.

  • Chris Wesley 4 years ago

    Wonderful stuff – thank you. On a point of grammar (because I’m an incurrable pedant) “Spectra” is the plural of “spectrum”. One spectrum – several spectra.

  • Beechwood Productions 4 years ago

    Hi, what determines if an electron drops an energy level or stays excited. Surely, when white light is passed through a gas, and the atoms become excited, they will then de-excite right away, and emit photons of the missing wavelengths (hence no gaps in the spectra are observed)?

  • Miguel De Zayas 4 years ago
  • James Robertson 4 years ago

    best of luck to England football team, 2018 World Cup!

  • Abhishek dudhat 4 years ago

    But hydrogen has one orbital so how it can go other orbital

  • Dylan 4 years ago

    Thank-you sir

  • asif alam joy 4 years ago

    Sir everything is right about your videos but I would suggest you to talk a slow pace so that some of the slow learners can keep track with.

  • Sidra-tul-muntaha 4 years ago

    I love this channel, so colorful and clear

    • Physics Online 4 years ago

      Thank you, physics shouldn’t be dull!

  • Marie Hill 3 years ago

    Are we expected to know all the energy levels in the OCR A book for a hydrogen atom? (Ground state being -13.6 to highest energy level being -0.54)?

    • Physics Online 3 years ago

      No, you don’t need to remember the exact figures.

    • Marie Hill 3 years ago

      GCSE and A Level Physics Online phew! Thank you!

  • Marie Hill 3 years ago

    Also, please could you explain how a cooler gas is able to contribute to an absorption spectrum and a hotter gas is able to contribute to an emission spectrum?

    • Eddie Profaska Dzankic PAGY 3 years ago

      not sure if I can answer this well, but for an atom to emit fotons(emission) it needs to gain energy, a.k.a heat. And for us too see what wavelenghts it absorbs(absorption) we need a cool gas, since it’s at it’s basic energi levels a.k.a all the electrons are in their “basic” energy level, ready to absorb the energy of the fotons to move up a level.

    • Marie Hill 3 years ago

      Eddie Profaska Dzankic PAGY that kinda makes sense. Thanks!

  • Deepak Sharma 3 years ago

    Very nice Explained , thanks

  • Deepak Sharma 3 years ago


  • Anu 2 years ago

    Thank you so much! This really help me understand the concept!!

  • yoobi 2 years ago

    nice lego models

Comments are closed.