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!
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.
There is a mistake in this video: The emission specra should have more lines than the absorption spectra, not the same amount. This is because when an electron is de-excited, it can come down in stages. i.e from n=4 to n=3, then to the ground state, with each change in energy level releasing a photon of a certain colour. So more colours are shown in the emission spectra than are blacked out in the absorption spectra.
That is a very good point! You’re absolutely right, and that’s how some materials can be excited by UV radiation then emit visible light as they go back to their ground state.
Isn’t the absorption spectra all the possible paths going up? It isn’t just considering the path from ground state. It also considers n=4 to n=5 or n=2 to n=4 etc.
@@volatiledinosaur8517 An excited electron will jump up energy levels. lets say from n=1 to n=3. Now to get back to n=1 it can take 2 paths. n=3 ----> n=1 or n=3 -----> n=2 ------> n=1. When they terminate at n=1 it is called the lyman series. The energy of the photon emitted when n=3 ----> n=1 will be greater than n=3 -----> n=2, because the energy difference between n=3 -----> n=1 is greater than n=3 ------> n=2. Therefore the photon will have a higher frequency.
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?
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)?
I know this was a long time ago, but the answer is that the photons are emitted in all directions - not just the direction that you're looking at the gas from. If the source of the white light is behind the gas, then some of that light won't carry on towards you (the observer), but instead will get emitted away from your eyes - hence darker. SOME of the light will, of course, be emitted in your direction - just not all of it.
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?
That's a very good question! The interior of the star is very hot indeed and emits white light of all wavelengths. HOWEVR, this light has to pass through the cooler outer layer of the star and also the vacuum as a result certain wavelengths are absorbed. xD hope this helps after 3 years!!
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.
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.
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.
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.
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 :)
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?
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...
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.
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.
is the emission spectra for each type of atom the same? because cant the electrons de-excite in different stages and hence produce different emission spectra? little confused there.
+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 ;-)
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?
Cool gas has its electrons at ground state. It, therefore, doesn't emit any photons. This is why it's used for absorption spectrum and can't be used for emission spectrum. Hot gas has electrons at various energy levels. It emits various wavelengths. This is why it used for emission spectrum. If hot gas is used for absorption spectrum, it can/will absorb many for frequencies than the cold gas. I think it can still be used for absorption spectrum but it overcomplicates things. ^please correct if wrong
5:30 am revision- exams in 3 and a half hours... quality videos mate, if only I had found them sooner
At least you have them now for the Depth and also for all of the year 13 content.
+A Level Physics Online true, many thanks for the time you've took to explain the topics
Good luck in your exam
What did you get?
@@MrCoolstopmotion bru that was 5 years ago
Thank you so much for this. Got my exam in an hour, this is the first time anyone's ever clearly explained these weird black lines to me.
OMG KING OF PHYSICS! thanks for this video. Exam's in a week....
+necrobreen Good luck
does the black line on the emission spectra mean that the photon emit light in all directions.
exams in abt 14 hours, thanks for everything man, rlly helped sum up quantum physics
I spent 3 weeks trying to understand this ........
Should have RUclips this up ...Awesome work sir
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!
That is fantastic - message me with your college name and I can send some more through.
You're such a lad
A level physics students 7 years on still be hating this topic
Each of your videos deserve at least 1 million views!! It's that good!!!
+Viki awesome Thanks (I wish it does get that big!)
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.
Fantastic video thank you, this helped me with my A-Levels so much!
+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....
Thanks
I love this channel, so colorful and clear
Thank you, physics shouldn't be dull!
one of the best explanations i've seen! studying for my exam later today :)
Great videos. What I needed just 5 days before the exam :')
Amazing! Keep it up, man!
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!
There is a mistake in this video:
The emission specra should have more lines than the absorption spectra, not the same amount. This is because when an electron is de-excited, it can come down in stages. i.e from n=4 to n=3, then to the ground state, with each change in energy level releasing a photon of a certain colour. So more colours are shown in the emission spectra than are blacked out in the absorption spectra.
That is a very good point! You’re absolutely right, and that’s how some materials can be excited by UV radiation then emit visible light as they go back to their ground state.
Isn’t the absorption spectra all the possible paths going up? It isn’t just considering the path from ground state. It also considers n=4 to n=5 or n=2 to n=4 etc.
@@volatiledinosaur8517 An excited electron will jump up energy levels. lets say from n=1 to n=3. Now to get back to n=1 it can take 2 paths. n=3 ----> n=1 or n=3 -----> n=2 ------> n=1. When they terminate at n=1 it is called the lyman series. The energy of the photon emitted when n=3 ----> n=1 will be greater than n=3 -----> n=2, because the energy difference between n=3 -----> n=1 is greater than n=3 ------> n=2. Therefore the photon will have a higher frequency.
isnt it possible to go up in stages as well, so why isnt it the same amount in the emission and absorption spectra
@@Shorty50 Don't forget the fondsworth oscillation
You've literally saved my life, great videos! Does this mean atoms absorb and emit the same frequency of photons?
hammyogunlayi Yes, their absorbtion and emission spectra are the same (but one is like the negative image of the other).
exam in one hour thanks :)
Outstanding!!! Thank you!!!
This video is very useful! Thank you!
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 that kinda makes sense. Thanks!
Thank you so much! This really help me understand the concept!!
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)?
Agreed. Can @PhysicsOnline answer this?
I know this was a long time ago, but the answer is that the photons are emitted in all directions - not just the direction that you're looking at the gas from. If the source of the white light is behind the gas, then some of that light won't carry on towards you (the observer), but instead will get emitted away from your eyes - hence darker. SOME of the light will, of course, be emitted in your direction - just not all of it.
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?
That's a very good question!
The interior of the star is very hot indeed and emits white light of all wavelengths. HOWEVR, this light has to pass through the cooler outer layer of the star and also the vacuum as a result certain wavelengths are absorbed.
xD hope this helps after 3 years!!
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.
BronzeJourney because even for just 1 electron there are many possible energy states it could exist in.
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.
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.
Great explaination :D
Higher physics test tmr! Cheers
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.
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 :)
Very nice Explained , thanks
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?
Not all green have the same energy level all have different energy level
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...
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.
Really good videos! Better than Dr PhysicsA
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.
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.
is the emission spectra for each type of atom the same?
because cant the electrons de-excite in different stages and hence produce different emission spectra? little confused there.
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)?
No, you don’t need to remember the exact figures.
GCSE and A Level Physics Online phew! Thank you!
Great video!!!!! Thank you
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
Very helpful, thank you
exams on friday shitting myself
But if transitions to n=1 gives out UV, how come you say that it emits a rainbow of colours?
Group 18 for ever!!!
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
Now this is cheeky
Thank you that very useful
Awesome!!
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??
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.
Thank-you sir
when electron de excitation why it come again to lower orbit
+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 ;-)
You cant run forever right?
i literally get goosebumps when i watch ur videos XD
whats 'n'?
For some reason we're learning this in Ireland as part of the Chemistry leaving Cert course 0.o
It's all good science!
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.
Great
a levels physics nice with model
Bruh. Cheers.
nice lego models
I'm curious is everyone here in there A-levels or is there anyone younger like me ?
Alex . Exe Most people are older, but that shouldn't stop you. Keep watch my and you'll find plenty of interest me material.
Black body radiation
i didn't understand anything
best of luck to England football team, 2018 World Cup!
Ur too quick :'(
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?
Cool gas has its electrons at ground state. It, therefore, doesn't emit any photons. This is why it's used for absorption spectrum and can't be used for emission spectrum.
Hot gas has electrons at various energy levels. It emits various wavelengths. This is why it used for emission spectrum. If hot gas is used for absorption spectrum, it can/will absorb many for frequencies than the cold gas. I think it can still be used for absorption spectrum but it overcomplicates things.
^please correct if wrong
@@qrroll109 2 years too late smh