Diffraction Gratings - A Level Physics

This video introduces and explains diffraction gratings for A Level Physics.
If you shine light, or other types of EM radiation, through a series of small slits, the waves interfere causing constructive and destructive interference at certain points. We can then use this method to calculate the wavelength of light. It is also why DVDs and CDs make beautiful rainbows.
Thanks for watching,
Lewis
This video is recommended for anyone studying A Level Physics in the following exam boards:
AQA
CIE
Edexcel
Edexcel IAL
Eduqas
IB
OCR A
OCR B
WJEC
_____________________________________
MY PHYSICS WEBSITES
Find even more videos organised by exam board and topic at:
GCSE Physics Online
► www.gcsephysic...
A Level Physics Online
► www.alevelphys...
MY KZbin CHANNEL
Your support in watching this video has been invaluable! To contribute towards the free videos on KZbin, make a small donation at:
► www.paypal.me/...
FOLLOW ME
► www.youtube.co...
► / physicsonline
► / gcseandalevelphysicson...
#waves #alevelphysics #physicsonline

[@aletheabarretto3624]

this channel literally the only thing getting me through physics

[@Yoshitha_bw]

Same

[@ramen5219]

The key to a good lecture: A short but to-the-point explanation ; to assure you don't lose focus and replaying won't be much of a hassle either. Thank you for this!

[@OpsSiolz]

i learn more in 6minutes than in a lecture at school

[@skattykid1562]

Well done mate u want us to suck u off

[@coolfred9083]

@@skattykid1562 What's your problem?

[@Dench773]

@@skattykid1562 wtf xD

[@aravindthebest1199]

@@skattykid1562 ok sir

[@kn-9325]

@@Dench773 ok pundei kabali

[@thenamelessshidposter1348]

As someone who has as of yet never done a proper lesson of A-level physics trying to understand some of the course before I start doing it in September, this was very well explained. Thanks very much.

[@PhysicsOnline]

Glad it was helpful!

[@kingrobert7246]

It isn’t as easy as this. But it’s a good start

[@kibsxkibbles7443]

Good luck on your first exam today!

[@thenamelessshidposter1348]

@@kibsxkibbles7443 Thanks but I dropped physics two years ago LOL 😭😭😭😭

[@kibsxkibbles7443]

@@thenamelessshidposter1348 oh LOL, you didn't miss much, just finished paper 1

[@tanishkaadeshmukh7139]

"horrendous DVD Frozen" lol

[@Stewartthorp]

Using to support my A level lessons thanks. The students learn more in 6min than....

[@PhysicsOnline]

That's great to hear! I made these for just that reason, to help students alongside their usual lessons.

[@makda971]

how did a levels go

[@pepsiman4418]

There's a reason this is your most viewed video, waves is probably the hardest year 1 subject, I'm not sure about year 2 but waves is done so early in the curriculum and is so hard

[@hamnachaudhary4657]

This lecture was sooo amazing. You taught us practically.

[@yn7751]

This is honestly a really great set of videos, thank you very much.

[@shella4016]

Brilliant, simple and concise! No bullshit. Saves time. Great vid

[@8OZntcs]

exam tommorow here I am again last day revision, anyone on the same boat?

[@tomstalley3179]

how did it go?

[@fabulo19]

I'm here the morning of my presentation at school, I am so screwed.

[@hanstonra]

lol same

[@matildemateus3977]

So are you in college by now

[@8OZntcs]

@@matildemateus3977 I've graduated with a first class in mechanical engineering :)

[@dll4042]

The best A level physics channel ever!

[@bismahkhan2682]

Watching this the night before my paper 1 at 4 in the morning. Wish me luck

[@stanpeter8098]

Thank you for saving me. You are one of the channels like Khan Academy and Science Shorts that don't put me to sleep! Thanks a lot for your resources!

[@PhysicsOnline]

Thank you, I try and make it as interesting as possible!

[@stanpeter8098]

Yup, your videos are 11/10 ;)

[@Szat1]

Keep these videos coming. These are really helpful!!

[@MrRaisin56]

wow this is such a good video, so well explained, makes it seem easy. very good job

[@Pineapple2349]

YOU SAVED MY FUCKING LIFE MAN THANK YOU

[@ketchurself7979]

Im wataching you because my teachers can't explain things. Started as level physics this september and i want to get A* at a level.

[@zoha1234]

Very well explained.This helped me a lot☺

[@mutasemwahbeh6954]

It was the best explanation thank you !

[@PhysicsOnline]

You are welcome!

[@kikisglam]

my all doubts are cleared by watching this....thanks

[@turipamuekazombiaze281]

man you really helped me out here ❤

[@GamezTUBER]

You are a legend!!! Thank you!!

[@faiyaznayeemhaque7316]

Thank you so much for this video

[@davidm3210]

Jolly good!

[@fromexoplanet21]

You saved me! Thanks💖

[@nafiafarzana9040]

That really helped me. Thanks a lot

[@yeanoorrahman8335]

Great vdo 🔥 I understood the whole thing in 6 min which i cound'nt by reading the book for an hour.

[@MiHaFi]

well done , very clear explanation , helped me a lot

[@noeditbookreviews]

Whoa, sweet interference pattern.

[@TKDS100]

you're a very good teacher, keep doing what you're doing

[@ALevelPhysicsOnlineYear13]

+TKDS Thanks

[@tanjimmahin8213]

best video for learning.................................

[@tanaka5269]

Well explained.Thank you very much

[@cruiser82]

Thank you so much sir, great video and great explanation.

[@continnum_radhe-radhe]

Nice ... Thank you

[@jorgeyboy3364]

very clearly explained, thanks

[@muhammadhamza4494]

Wow you explain really good !

[@zainabtahir3024]

I love how he writes

[@Panzermeister36]

Your video is really really helpful man! Thank you for your time

[@choi9453]

thank you so much^^

[@sidratulmuntahaahmed5786]

i stan this guy

[@quickmaths1102]

God bless you !!!!!!

[@198Immortal]

this is the first video i watched from your channel. I love your voice :) and you got a subscriber!

[@AmbieWolfie]

If you take Chemistry, E Rintoul has a similar voice and is brilliant at explaining chemistry concepts :)

[@maisamaskari8774]

Rintoul is the absolute best

[@fatmafaizal07]

could u do like an actual question on this? i didnt really get the part where u said we can find theta .. like is it the sin = opposite by hypotenuse way..?

[@frobekobe6757]

Wow these videos are great was wondering if you have made one for A2 contents

[@PhysicsOnline]

Frobe Kobe Yes I have, almost the whole course. Have a look on my website.

[@frobekobe6757]

can I have a link please

[@frobekobe6757]

This also covers everything on OCR B( Advancing physics) too right?

[@PhysicsOnline]

www.alevelphysicsonline.com

[@edi6323]

is this a practical video or just an excuse to hate on Frozen? Experts still don't know

[@moleily9743]

Thank you so much your video is very useful

[@ArnavSingh-hs5ex]

Frozen is a masterpiece

[@mantosh56]

Big hero 6 is much better

[@kimberlyannnn]

Thanks so much, very informative!

[@shathabarq4256]

Thank you!

[@joealex2463]

Does the distance between slits mean the same thing as lines per mm of the diffraction grating?

[@zarykodo5330]

Great vid keep it up

[@arromaljjayan8996]

Hello Mr Matheson Really amazing videos!! Just wanted to know if you would be going through A2 also....because literally, your videos very helpful to us students....we have full support for you sir!!

[@PhysicsOnline]

Arromal J Jayan Yes I will, still finishing off AS but A2 will be next!

[@Plankkkkk]

Thanks!

[@beaurogers7500]

great video and all (seriously) but why did you have to go so hard on that frozen DVD, it is not THAT bad.

[@akbaradilah6573]

Thanks bro👊

[@yffsvhf5669]

Thank you

[@notlouis3016]

How dare you slander the masterpiece that is frozen

[@dudeymabob4975]

How dare you exist

[@notlouis3016]

@@dudeymabob4975 sad

[@dudeymabob4975]

@@notlouis3016 Louis more like poouis

[@davididowu4442]

Just learnt grating in 6 mins after struggling with it for 9 months

[@TheKidThatCould]

so does theata change depending on the order your measuring from or is theata always the angle between the zero'th and first order???????

[@thefigmaster3519]

its between 0th and any order... the 'n' in the equation handles that.

[@sohaibbaig4655]

Even though your videos are amazing, the intro makes my ears bleed

[@spikedmini1234]

@physicsonline do AQA students need to know how to convert degrees into DMS for this topic?

[@professor7296]

do you had a video on Solid state physics

[@thetechrealms7824]

‘Horrendous’ is precisely how I’d describe it

[@danielsteel2617]

Do you know what are the applications of diffraction gratings

[@hotmemesinyourarea2997]

Frozen is horrendous u say, chad deteted opinion accepted

[@sumaalbayatee2122]

thankyou!!

[@JBCJackson]

Light consisting of two separate wavelengths, 450 nm and 650 nm, falls onto a diffraction grating. The grating is labelled 600 lines per mm. Calculate the angular separation between the first order maximum of the two wavelengths. Help please

[@PhysicsOnline]

+JBC Jackson Use the equation to find the angle theta for n=1 for each wavelength individually. You answer will then be the difference between these two values.

[@JBCJackson]

A Level Physics Online Thank you!

[@deez9189]

tysm

[@heinzarniaung2915]

"horrendous dvd frozen" I just want to know how many times Mr. Physics Online's kids forced him to watch it.

[@anawilliams1332]

Are you one of his students?

[@heinzarniaung2915]

@@anawilliams1332 obviously not

[@sufiyantaher593]

Outro gives me PTSD

[@CAL1MBO]

Does the maximum number of orders include the 0th as 1 of them? Or not at all?

[@sophiehasslauer2353]

I don't unterstand what a maxima is??? what do I have to understand by a maximum (definiton)?

[@mrboyban]

Is this the same video upload on Up-learn?

[@PhysicsOnline]

Yes it is, they use my material and have plenty of other questions too.

[@sofiaemberson6836]

Hi, I have some questions I’m really stuck in. How does rotating the diffraction grating ninety degrees affect the pattern produced? Also how does using a point source of white light affect the pattern produced? Thanks.

[@anawilliams1332]

White light will defract into all its wavelengths essentialy makeing a rainbow. As for rotateing i dont know of any effect of that, maybee you were thinking of a polarisation filter?

[@DraganaBogdanovic1]

Hello Mr Matheson, Amazing videos and very helpful! I wanted to ask where we can find 2015 past papers? (ocr board) Thank you very much :)

[@PhysicsOnline]

+Dragana Bogdanovic They're not available yet on their main website - but your teachers will have access to them.

[@sheheryaarmalik1179]

Which pen do you use?

[@endover422]

A question: how would you find/determine the center of let's say 1st order maximum? Is literally the geometrical center of the fringe, or the place where there is a green color?

[@yuno9121]

find the tree for the centre

[@aswin8063]

I have a doubt .. is diffraction and diffraction grating the same?

[@maisamaskari8774]

Horrendous Spot on

[@ameerkhilji9946]

Can someone please tell me if Increasing the number of lines per mm on a diffraction grating would increase the number of order of maxima?

[@sympeux]

Why exactly is theta different for different wavelenghts?

[@yuno9121]

maybe because different wavelengths have different angles

[@thefigmaster3519]

the amount of diffraction depends on how close the width of the slit is to the wavelength, so light of different wavelengths different amounts for a give slit width, resulting in different values for theta

[@henrytobiloba1703]

What happens when a grating of 600lines/mm is used in place of a 300 line/mm grating??

[@namansharma7948]

Hey i think that the formula is 2d sinθ=n× lanbda and i have a doubt that we can take any value of n. For example- we have 3 dispersed laser pt so we can put value of n= 1 or 2 or 3. Pls reply

[@chrismcmillan3003]

that's for a single slit dispersion I think

[@jacobvandijk6525]

It is one MAXIMUM and two or more MAXIMA.

[@Moinul987]

What board are these videos mainly focused on?

[@PhysicsOnline]

Moinul Islam Mainly OCR Spec A, but there is some content for some of the Edexcel and AQA units (I'm still working on the rest of this content), although physics is still physics whichever board you're sitting which is why I haven't mentioned any exam boards in particular in my videos.

[@TheSamaa1997]

A Level Physics Online I'm taking IGCSE and it helped me a lot! Thank you so much!

[@chocolatebat21]

Very helpful video

[@Monacosuper]

Would the path difference for the first order be lambda or 2lambda??

[@PhysicsOnline]

It would be lambda.

[@CAL1MBO]

The second order is 2lambda.

[@ahmadhassankhan703]

What is d?? The distance between 1st order and O order for example??

[@sea5205]

Ahmad Hassan Khan distance between slits

[@aryanahsan4381]

hey is this in AS or A level? thanks

[@abduboqiyevdovudxon4494]

AS

[@jordanrandal5540]

Where can I get a 300 lines/mm diffraction grating exactly like the one you used at 44 seconds into your video? My diffraction grating has 1000 lines/mm and it does not produce higher order image pairs like the one you used in your video. It would mean a lot to me to get the 300 lines/mm grating you used and show my Dad that is does indeed produce higher order image pairs as shown in your video.

[@PhysicsOnline]

Pls AJ I just found this one in a cupboard at school. Could you borrow one from your teacher, and a small red laser, to use at home?

[@jordanrandal5540]

I'm in the fifth grade at my school. We haven't talked about lasers or diffraction gratings yet. It's my Dad that bugs me about this stuff. At home we got some diffraction gratings that have 1000 lines/mm and a red laser pointer but it doesn't work. We only get 3 dots no matter what we try. We don't get higher order image pairs like you do in your video. So we are getting more diffraction gratings with less lines per mm. Yours has 300 lines/mm. In a few days we will be able to try this with 100, 300, and 600 lines/mm. It will mean a lot to my Dad to see the higher order image pairs in his lifetime.

[@linaabdelshafy6524]

frozen is not horrendous what are you talking about mate? great video tho

[@rebeccatan4676]

Single-slit experiment vid?

[@sourdawg7001]

why u hate frozem

[@minecraftfan2087]

Hey, listen buddy. I like FROZEN, so don't you dare call it a horrendous dvd.

[@lukemcellin8736]

POV: ur Reading though the comments and not watching the video

[@PhysicsOnline]

Want to see more videos I've made? Have a look at this video: kzbin.info/www/bejne/omqsppR-dsx6as0 What else should I make videos on next?

[@emakhatun3524]

+A Level Physics Online in your videos could you please go over exam style questions?

[@PhysicsOnline]

I will soon make videos for all the past exam papers too.

[@HIGHERPROSPECTZDNB]

+A Level Physics Online Have you got any videos on particle physics, i.e. antiparticles, leptons, hadrons, quarks etc?

[@PhysicsOnline]

Not yet - I will do in the next month though!

[@ss-sv4vj]

A Level Physics Online can you make some on Simple Harmonic Motion

[@dudeymabob4975]

Flewis flerry uwu

[@jeyaneepan]

CAN YOU SOLVE THIS PROBLEM? consider a one-dimensional array of scatterers with spacing s=1.5 microns. I shine a light of 532 nm wavelength perpendicularly onto this array and look at the back-scattered light on a screen far from the array. How many diffraction "spots" should I see on the screen? Please enter an integer number.

[@WaddiaS]

d = 1.5 x 10^-6 m lambda = 532 x 10^-9 m For maximum n of fringes/ spots, theta = 90 therefore n = (d.sintheta)/ lamba You're gonna observe 2.8x2 = approx 6 diffraction spots Correct me if my discretion is wrong. And thanks for the food for thought :)

[@jeyaneepan]

thanks.

[@rubaetm5353]

i hate frozen but nice video