about fiber optic refraction


by kelvin_ng
Tags: fiber, optic, refraction
kelvin_ng
kelvin_ng is offline
#1
Sep11-07, 01:52 PM
P: 7
Question:

A ray of light enters a light fiber at an angle of 15degree with the long axis of the fiber. Calculate the distance the light ray travels between succesive reflections off the sides of the fiber has an index of refraction 1.6 and is 10[tex]^{-4}[/tex]mm in diameter.
Phys.Org News Partner Science news on Phys.org
Cougars' diverse diet helped them survive the Pleistocene mass extinction
Cyber risks can cause disruption on scale of 2008 crisis, study says
Mantis shrimp stronger than airplanes
kelvin_ng
kelvin_ng is offline
#2
Sep11-07, 01:55 PM
P: 7
the answer given is L = 3.9 x 10[tex]^{-4}[/tex] m.
kelvin_ng
kelvin_ng is offline
#3
Sep11-07, 01:58 PM
P: 7
what is the solution to this question?
I just can't get to the answer.

kelvin_ng
kelvin_ng is offline
#4
Sep11-07, 02:12 PM
P: 7

about fiber optic refraction


is it using n = sine i/sine r or n = 1 / sine c?
and is it i = 90degree - 15degree = 75degree?
i don't know actually what the question mean by.
Can someone help me?
learningphysics
learningphysics is offline
#5
Sep11-07, 02:22 PM
HW Helper
P: 4,125
Quote Quote by kelvin_ng View Post
is it using n = sine i/sine r or n = 1 / sine c?
and is it i = 90degree - 15degree = 75degree?
i don't know actually what the question mean by.
Can someone help me?
I think index of refraction = sin(angle of incidence)/sin(angle of refraction)
learningphysics
learningphysics is offline
#6
Sep11-07, 02:26 PM
HW Helper
P: 4,125
Quote Quote by kelvin_ng View Post
is it using n = sine i/sine r or n = 1 / sine c?
and is it i = 90degree - 15degree = 75degree?
i don't know actually what the question mean by.
Can someone help me?
I think you need to use 75 degrees.
kelvin_ng
kelvin_ng is offline
#7
Sep13-07, 03:37 AM
P: 7
but then i get the angle of refraction is 37.14 degree.
then what else i could do to get L = 3.9 x 10[tex]^{-4}[/tex] m ?
Sleek
Sleek is offline
#8
Sep13-07, 04:44 AM
P: 59
I don't think the angle of reflection has anything to do with the refractive index, if total internal reflection takes places.

"A ray of light enters a light fiber at an angle of 15degree with the long axis of the fiber. Calculate the distance the light ray travels between succesive reflections off the sides of the fiber has an index of refraction 1.6 and is 10^-4mm in diameter."

I get an answer 3.7320508075688776*10^-4 using a computer.

We find that tan(incidence)=diameter/(distance between each reflection)

Therefore tan(pi/12)=10^-4/x

Regards,
Sleek.
kelvin_ng
kelvin_ng is offline
#9
Sep13-07, 04:48 AM
P: 7
lolx, i know what to do now.
I just get the answer.
Just by using trigonometri. 10^-4 / sin 15 to find the hipotenus.
Sleek
Sleek is offline
#10
Sep13-07, 04:52 AM
P: 59
Ops, I think i blundered. I found the length of fiber traveled by light instead. Yes, you have to use sine. Answer come out to be 3.86*10^-4 ~ 3.9*10^-4mm. Sorry about that.
kelvin_ng
kelvin_ng is offline
#11
Sep13-07, 05:29 AM
P: 7
No need to sorry.. ^^
Is very nice that u guyz is tryin to help.


Register to reply

Related Discussions
fiber optic coupling question General Physics 8
laser through optic fiber - out before through General Physics 7
going completely fiber optic computers Computing & Technology 7
glass fiber v's carbon fiber Materials & Chemical Engineering 0
fiber optic cabling Computing & Technology 2