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question about diffraction of waves

when the wavelength of a wave is about the same as the width of the slit of the diffraction grating, waves diffract. But what happens if the slits are larger? and what happens when the wavelength is a lot greater than the width of the slit?
If the gap is slightly larger than the wavelength, diffraction will only occur at the edges. If the gap is a lot larger, then diffraction will be minimal.
Reply 2
Avatar for max smith
max smith
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Original post by FopePrancis
If the gap is slightly larger than the wavelength, diffraction will only occur at the edges. If the gap is a lot larger, then diffraction will be minimal.


Ok thank you, but what if the gap is a lot smaller than the wavelength? will it still diffract?
Original post by Jules kemps
Ok thank you, but what if the gap is a lot smaller than the wavelength? will it still diffract?


Yes. The smaller the gap, the greater the diffraction effect. :smile:
Reply 4
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piketty6
Original post by Jules kemps
when the wavelength of a wave is about the same as the width of the slit of the diffraction grating, waves diffract. But what happens if the slits are larger? and what happens when the wavelength is a lot greater than the width of the slit?


IF you're doing OCR physics A, you need to understand when the wavelength and size of gap is comparable and similar, max diffraction occurs
S=Slit width/ wavelength

S is value of diffraction.
This formula helps realise both wavelength and slit width have the same impact. If both icnrease by 5 then nothing changes. If they change by different amounts then the amount of diffraction changes

When the width of the slit/gap is decreased, the width of the diffraction interference pattern is incrwaed . When the slit width becomes too small the diffraction fringes become so wide that it becomes difficult to tell apart between the dark and light lines

you should learn to explain it and desribe the patterns of areas of minima and maxima.
Reply 6
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max smith
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Original post by FopePrancis
Yes. The smaller the gap, the greater the diffraction effect. :smile:


Original post by piketty6
IF you're doing OCR physics A, you need to understand when the wavelength and size of gap is comparable and similar, max diffraction occurs


But if piketty6 is correct, then as the gap gets smaller than the wavelength, the amount of diffraction would decrease again? these statements contradictory
Original post by Jules kemps
But if piketty6 is correct, then as the gap gets smaller than the wavelength, the amount of diffraction would decrease again? these statements contradictory


What? You trippin? @piketty6 stated that if the size of the gap and the wavelength is similar or comparable, then maximum diffraction would occur, which is essentially what I said.

You need to do some revision m8.
Reply 8
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philipd
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Original post by FopePrancis
What? You trippin? @piketty6 stated that if the size of the gap and the wavelength is similar or comparable, then maximum diffraction would occur, which is essentially what I said.

You need to do some revision m8.



Read what he's written. Yes, maximum diffraction occurs when wavelength=slit width. If you decrease the width of the slit, then the amount of diffraction would reduce. He's right, you're wrong. I'd get revising yourself fella.
Reply 9
Avatar for max smith
max smith
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Original post by FopePrancis
What? You trippin? @piketty6 stated that if the size of the gap and the wavelength is similar or comparable, then maximum diffraction would occur, which is essentially what I said.

You need to do some revision m8.


i'm trying to understand. so when the wavelength is similar or comparable then you have maximal diffraction. I understand that!. But your first statement says, as the gap size decreases, diffraction increases. How is it possible if there is a tiny gap and a massive wavelength, they obviously are not comparable? That really confuses me
Reply 10
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max smith
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Original post by philipd
Read what he's written. Yes, maximum diffraction occurs when wavelength=slit width. If you decrease the width of the slit, then the amount of diffraction would reduce. He's right, you're wrong. I'd get revising yourself fella.


Thank you so much this was so helpful!
Original post by Jules kemps
i'm trying to understand. so when the wavelength is similar or comparable then you have maximal diffraction. I understand that!. But your first statement says, as the gap size decreases, diffraction increases. How is it possible if there is a tiny gap and a massive wavelength, they obviously are not comparable? That really confuses me


The first statement isn't true
Original post by Jules kemps
Thank you so much this was so helpful!


Have a read around the subject. I think most boards just want you to know that max diffraction occurs when wavelength=slit width.
Original post by Jules kemps
i'm trying to understand. so when the wavelength is similar or comparable then you have maximal diffraction. I understand that!. But your first statement says, as the gap size decreases, diffraction increases. How is it possible if there is a tiny gap and a massive wavelength, they obviously are not comparable? That really confuses me


If the gap is smaller than the wavelength, diffraction still occurs with a larger and larger angle, but at the same time less and less of the wave will go through the gap. Tiny tiny openings, much smaller than the wavelength, act like point sources and send waves out in all directions--a sort of maximum diffraction.

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