Critical angle
I had done:
1.96/2.03 = 0.97 = refractive index
since 1/sinC = refractive index, I tried to find the critical angle but the maximum value of sin is 1 so it didn't work!
How should I go about this question?? Can someone please explain it to me in simple terms. Furthermore, why is 1/sinC = refractive index??
The equatioin is refractive index = sin i/sin r
Since at the critical angle, sin r is 90, shouldn't it be sin i = refractive index?
1.96/2.03 = 0.97 = refractive index
since 1/sinC = refractive index, I tried to find the critical angle but the maximum value of sin is 1 so it didn't work!
How should I go about this question?? Can someone please explain it to me in simple terms. Furthermore, why is 1/sinC = refractive index??
The equatioin is refractive index = sin i/sin r
Since at the critical angle, sin r is 90, shouldn't it be sin i = refractive index?
Scroll to see replies
To find the critical angle of a material, you have to go from the denser medium, so i is actually r and r is actually i. So you can either swap them around or do sin(r)/sin(i) = sin(c)
Original post by mclean_tom_
To find the critical angle of a material, you have to go from the denser medium, so i is actually r and r is actually i. So you can either swap them around or do sin(r)/sin(i) = sin(c)
Is that always the way to find critical angle?
And when it says "refractive index of glass", which one out of the incident angle and refractive angle is the angle fir glass? This always confuses me
Posted from TSR Mobile
If you are doing the critical angle, you have to go from the denser medium. So in this one, you have to do
Refractive index = 2.03/1.96 = 1.036
If you think about it, the refractive index has to be bigger than 1 because the light is slowing down.
Then, you can use sin(i) = 1 / 1.03
i = sin-1(1/1.03) = 75º
Remember, in critical angles you have to go from the denser medium and that sin(r) = 1 because r = 90.
Refractive index = 2.03/1.96 = 1.036
If you think about it, the refractive index has to be bigger than 1 because the light is slowing down.
Then, you can use sin(i) = 1 / 1.03
i = sin-1(1/1.03) = 75º
Remember, in critical angles you have to go from the denser medium and that sin(r) = 1 because r = 90.
Original post by mclean_tom_
If you are doing the critical angle, you have to go from the denser medium. So in this one, you have to do
Refractive index = 2.03/1.96 = 1.036
If you think about it, the refractive index has to be bigger than 1 because the light is slowing down.
Then, you can use sin(i) = 1 / 1.03
i = sin-1(1/1.03) = 75º
Remember, in critical angles you have to go from the denser medium and that sin(r) = 1 because r = 90.
Refractive index = 2.03/1.96 = 1.036
If you think about it, the refractive index has to be bigger than 1 because the light is slowing down.
Then, you can use sin(i) = 1 / 1.03
i = sin-1(1/1.03) = 75º
Remember, in critical angles you have to go from the denser medium and that sin(r) = 1 because r = 90.
Yes, i understood that, thanks.
But in other questions when it says "the refractive angle of glass", is glass the 2nd medium? Like, in the equation sin i/sin r, is r the angle to the normal for the glass?
Posted from TSR Mobile
Original post by jtbteddy
Yes, i understood that, thanks.
But in other questions when it says "the refractive angle of glass", is glass the 2nd medium? Like, in the equation sin i/sin r, is r the angle to the normal for the glass?
Posted from TSR Mobile
But in other questions when it says "the refractive angle of glass", is glass the 2nd medium? Like, in the equation sin i/sin r, is r the angle to the normal for the glass?
Posted from TSR Mobile
Yes
If you get a number bigger than 1 for refractive index, you are most likely correct
When you're just given the refractive index, it's the index from a vacuum into that material. Also the same as the speed of light in a vacuum divided by the speed of light in that material. Critical angle is the incident angle required to give a 90 degree refraction (and thus go along the normal)
Original post by mclean_tom_
Yes
If you get a number bigger than 1 for refractive index, you are most likely correct
If you get a number bigger than 1 for refractive index, you are most likely correct
Original post by lerjj
When you're just given the refractive index, it's the index from a vacuum into that material. Also the same as the speed of light in a vacuum divided by the speed of light in that material. Critical angle is the incident angle required to give a 90 degree refraction (and thus go along the normal)
My question is, when it says "the refractive index of x", x is always the 2nd medium right?
In this question, could you help me draw the line outside the prism? I know that for a denser solution, the line inside the prism will be closer to the normal, but how is it meant to be drawn out of the prism?
Thanks for your help
Original post by jtbteddy
So in this example, medium 1 is air, and medium 2 is the plastic layer and it's called "the refractive index of the plastic layer"?
My question is, when it says "the refractive index of x", x is always the 2nd medium right?
In this question, could you help me draw the line outside the prism? I know that for a denser solution, the line inside the prism will be closer to the normal, but how is it meant to be drawn out of the prism?
Thanks for your help
My question is, when it says "the refractive index of x", x is always the 2nd medium right?
In this question, could you help me draw the line outside the prism? I know that for a denser solution, the line inside the prism will be closer to the normal, but how is it meant to be drawn out of the prism?
Thanks for your help
Do you know Snell's law? If you do you should be able to work this out by yourself. You can make up numbers for the refractive index and draw out the answers if you want as long as the denser medium (high sugar conc.) has a larger refractive index than the lower medium (low sugar conc.)
If you're still stuck I'll help you later
Original post by lerjj
Do you know Snell's law? If you do you should be able to work this out by yourself. You can make up numbers for the refractive index and draw out the answers if you want as long as the denser medium (high sugar conc.) has a larger refractive index than the lower medium (low sugar conc.)
If you're still stuck I'll help you later
If you're still stuck I'll help you later
Yeah i do, but i dont know how a more concentrated solution links with velocity or how big/small the angle if refraction is.. And i know that inside the prism the more concentrated solutions path will be towards the normal, as i was taught this at school, but what about outsude the prism?
Posted from TSR Mobile
Original post by lerjj
The more concentrated solution has a higher refractive index lower speed of light.
Does that help? I can probably go through it for you, but it would be better if you went through it using Snell's law to see how that different angles change.
Does that help? I can probably go through it for you, but it would be better if you went through it using Snell's law to see how that different angles change.
Refractive index is a measure of how close the path is to the normal right? So the more concentrated solution will have a path closer to the normal?
Since refractive index = v1/v2, that explains why it has a lower speed?
Original post by jtbteddy
Refractive index is a measure of how close the path is to the normal right? So the more concentrated solution will have a path closer to the normal?
Since refractive index = v1/v2, that explains why it has a lower speed?
Since refractive index = v1/v2, that explains why it has a lower speed?
Original post by lerjj
Kkay, thanks. But is refractive index a measure of how close the path is to the normal?
Original post by jtbteddy
Kkay, thanks. But is refractive index a measure of how close the path is to the normal?
No, not really, it's a measure of how much refraction takes place. Less dense to more dense--> towards the normal
more dense to less dense--> away from normal.
So to answer the original question with the prism, the refraction will be greater both entering and exiting, which means that it will first move more towards and later more away from the normal. Does that make sense?
P.s. check that using snell's law because I haven't drawn out the diagram personally.
Original post by lerjj
No, not really, it's a measure of how much refraction takes place. Less dense to more dense--> towards the normal
more dense to less dense--> away from normal.
So to answer the original question with the prism, the refraction will be greater both entering and exiting, which means that it will first move more towards and later more away from the normal. Does that make sense?
P.s. check that using snell's law because I haven't drawn out the diagram personally.
more dense to less dense--> away from normal.
So to answer the original question with the prism, the refraction will be greater both entering and exiting, which means that it will first move more towards and later more away from the normal. Does that make sense?
P.s. check that using snell's law because I haven't drawn out the diagram personally.
Yup, it does. Thank you very much
Posted from TSR Mobile
Original post by lerjj
No, not really, it's a measure of how much refraction takes place. Less dense to more dense--> towards the normal
more dense to less dense--> away from normal.
So to answer the original question with the prism, the refraction will be greater both entering and exiting, which means that it will first move more towards and later more away from the normal. Does that make sense?
P.s. check that using snell's law because I haven't drawn out the diagram personally.
more dense to less dense--> away from normal.
So to answer the original question with the prism, the refraction will be greater both entering and exiting, which means that it will first move more towards and later more away from the normal. Does that make sense?
P.s. check that using snell's law because I haven't drawn out the diagram personally.
Nvm. Got it. Thanks
(edited 9 years ago)
Original post by jtbteddy
Nvm. Got it. Thanks
Do you want help with that question as well? I think violet light refracts more strongly than red light.
Original post by lerjj
Do you want help with that question as well? I think violet light refracts more strongly than red light.
Yupp, youre right:
Violet refracts the most, i.e. Its angle of refraction is the smallest.
Got it
thanks!Posted from TSR Mobile
Original post by jtbteddy
Yupp, youre right:
Violet refracts the most, i.e. Its angle of refraction is the smallest.
Got it thanks!
Posted from TSR Mobile
Violet refracts the most, i.e. Its angle of refraction is the smallest.
Got it
thanks!Posted from TSR Mobile
It's angle of refraction is the largest you mean? It's 4.61 degrees more.
But yeah, that diagram is perfect so just use that for all future queries re refraction.
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