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MrNeuro

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Would it be correct to say that blue light has the smallest angle of refraction (in relation to the normal)

b/c snells states n1 sin(theta1) = n2 sin(theta 2)
1(theta 1) / n2 = sin theta 2

n2 is the largest for blue light and smallest for red light hence blue should have the smallest angle of refraction.... pretty sure this is right just looking for verification
 

chiddler

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yes. blue light diffracts the most and therefore has the highest n value and slowest speed.

remember violet is even slower and higher n value.
 

pm1

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Would it be correct to say that blue light has the smallest angle of refraction (in relation to the normal)

b/c snells states n1 sin(theta1) = n2 sin(theta 2)
1(theta 1) / n2 = sin theta 2

n2 is the largest for blue light and smallest for red light hence blue should have the smallest angle of refraction.... pretty sure this is right just looking for verification

I just posted a thread about this... apparently when dispersion happens there is an exception. Blue would have a smaller n and it will bend the most. However, I'm not quite sure the reasoning behind this exception.. :(
 

chiddler

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I just posted a thread about this... apparently when dispersion happens there is an exception. Blue would have a smaller n and it will bend the most. However, I'm not quite sure the reasoning behind this exception.. :(

which thread, please?

0fTWQ.png


generally speaking, a small n value means that there is very little diffraction going on (ie light bends less). a large n value means there is a lot of diffraction going on (ie the light bends more).

we both know that blue light bends more and therefore it has a larger n value than red light. the higher the frequency of light, the lower the velocity. therefore, purple moves the slowest, has the largest n value, and diffracts the most.
 
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MrNeuro

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I just posted a thread about this... apparently when dispersion happens there is an exception. Blue would have a smaller n and it will bend the most. However, I'm not quite sure the reasoning behind this exception.. :(
no i think your mistaken

blue light will have a larger n

it comes from snells law

n1sin𝛳1 = n2sin𝛳2
sin𝛳1 / sin𝛳2 = n2 / n1 = v1/ v2 = λ1f1 / λ2f2

hence the dispersion angle is dependent upon either λ or frequency and a lower wavelength (blue) will have a higher refractive index and a smaller angle of refraction
 

pm1

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no i think your mistaken

blue light will have a larger n

it comes from snells law

n1sin𝛳1 = n2sin𝛳2
sin𝛳1 / sin𝛳2 = n2 / n1 = v1/ v2 = λ1f1 / λ2f2

hence the dispersion angle is dependent upon either λ or frequency and a lower wavelength (blue) will have a higher refractive index and a smaller angle of refraction

yes, I'm pretty sure I'm mistaken too.. hehe I'm trying to figure this out. Is the angle of refraction and diffraction interchangeable? how come blue light has a larger n? why is it slower?
 

pm1

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which thread, please?

0fTWQ.png


generally speaking, a small n value means that there is very little diffraction going on (ie light bends less). a large n value means there is a lot of diffraction going on (ie the light bends more).

we both know that blue light bends more and therefore it has a larger n value than red light. the higher the frequency of light, the lower the velocity. therefore, purple moves the slowest, has the largest n value, and diffracts the most.

this makes sense.. but if you don't mind reading this thread.. http://forums.studentdoctor.net/showthread.php?t=906433
 

pfaction

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I'm gonna regurg what I know:

Higher index = more bend.

Higher frequency = higher index = more bend.

Lower lamda = higher index = more bend.

Violet is the slowest, highest index, bends the most.
Red is the fastest,lowest index, bends the least.
 

chiddler

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this makes sense.. but if you don't mind reading this thread.. http://forums.studentdoctor.net/showthread.php?t=906433

you need to organize your posts a little more nicely! people are more likely to read them that way.

i disagree with your premise that red light moves slowest.

Light_dispersion_conceptual_waves.gif


notice that read light moves faster than the purple. is not meant to be taken as the literal speed of light of course, but, as the title of the image suggests if you check the url, it is meant for conceptualization.
 

pm1

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I'm gonna regurg what I know:

Higher index = more bend.

Higher frequency = higher index = more bend.

Lower lamda = higher index = more bend.

Violet is the slowest, highest index, bends the most.
Red is the fastest,lowest index, bends the least.

thanks!
 
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