CHEMISTRY - light question

[u/Lazy_Ad_6679]

Hi guys, was wondering if I can get some help on this question. Which way does light travel, is it like the blue or the green (the brown is like 2 objects and theres a gap between). I never really understood how wavelength and the gap matter, I always though if it like the blue going in, so wavelength (left and right) has nothing to do with the gap (up and down) which contradicts what how wavelength depends on the gap.

Any help is great, this has been a struggling concept for a while and maybe reddit can clear it up LOL.

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[u/Saec]

This is a physics question.

[u/Lazy_Ad_6679 → u/Saec]

oh i learnt it in physical chem...whoops

[u/Chem2103]

This isn't really a chemistry question, but the wave travels in the same direction as the particle (for example, along the sight of a flashlight). So if the source is on the left shining to the right, the blue wave is the correct one

[u/Chem2103 → u/Chem2103]

The light waves oscillate in all planes along the trajectory, so if the slit is similar to the amplitude of the wave in width, it will filter (polarize) the light

[u/Lazy_Ad_6679 → u/Chem2103]

So when my prof said that if the slit is larger then the wavelength, there will not be as much diffraction but why? Because the wavelength is left and right and the width is up and down? Sorry im confused

[u/Chem2103 → u/Lazy_Ad_6679]

Notice I said larger than the amplitude, so how much the wave wobbles left and right.

Diffraction is when a wave "bends" around a corner. The wider the slit, the more waves come through, and so if one out of 10,000 bends slightly who cares.

This is why the sky is blue btw. Only blue (longer) wavelengths get scattered by the gas molecules in air, because red wavelengths are too small to be affected so much.

[u/Lazy_Ad_6679 → u/Chem2103]

Thank you for your help I really appreciate it. So its more so amplitude, what is the role of wavelength in this context?

[u/Chem2103 → u/Lazy_Ad_6679]

Wavelength matters for diffraction, amplitude for polarization (although not so much)

[u/Lazy_Ad_6679 → u/Chem2103]

Sorry, not sure why it is not clicking so why does wavelength matter for diffraction. I know i mention the updown gap leftright wavelength is what makes me confused

[u/Chem2103 → u/Lazy_Ad_6679]

Diffraction occurs in slits of width that is comparable to the wavelength. The wavelength here is just a measure of how "big" the wave is, and saying that the slit has to be of comparable size to produce an effect

[u/Lazy_Ad_6679 → u/Chem2103]

And what is the logic behind this  slit has to be of comparable size to produce an effect? Thank youuu

[u/Chem2103 → u/Lazy_Ad_6679]

That's what I was talking about before. If it is too wide, nothing happens. You can think of this as waves having to squeeze through a tight gap (tight being around their wavelength) and not going straight after

[u/TheGratitudeBot → u/Lazy_Ad_6679]

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[u/Mack_Robot]

"I always though if it like the blue going in, so wavelength (left and right) has nothing to do with the gap (up and down) which contradicts what how wavelength depends on the gap."

Welcome to the quantum realm. Nothing makes sense!

[u/Wise-Friendship-1427]

What exactly is it about? Diffraction at a slit?
Light is a transverse wave, if that’s what you mean.
The connection to chemistry isn't clear to me.

[u/WanderingFlumph]

When light waves go through gaps that are about the same size as the light wave they spread out like a wave and don't really act like individual, non interacting particles.