here are 2 questions in trig. I can't figure out?

Question

1. A light ray attempts to pass from a material with an index of refraction of 2.48,?
into a material with an index of refraction of 1.74. Find the initial angle of the light ray necessary to achieve total internal reflection?
2. Execute the research to explain how Snell's Law and the process of total internal reflection make it possible for fiber-optic cables to convey data in today's computer dependant marketplace?

Answer 1

1. The critical angle of refraction for a ray encountering an interface between two materials with refractive indices n1 (the first material) and n2 (the second material), where n1 > n2 is (see first source):

sin(critical angle) = n2/n1

critical angle = arcsin(n2/n1)

In your case,

critical angle = arcsin(1.74/2.48) = 0.778 radians = 44.557 degrees.

2. Use your favorite internet search engine to do a search for the keywords: total internal reflection fiber optic. You'll get zillions of relevant hits. See second source for a start.

Answer 2

(1)
Snell's Law says

n1*sin(Θ1) = n2*sin(Θ2)

Where Θ1 in the angle between the ray and a normal to the interface between the two materials, n1 is the index of refraction of the material, and Θ2 and n2 are the same for the second material.

The critical angle accurs when the ray passing from the greater refractive index to the smaller refractive index (say n1 > n2) exits at 90 degrees. So the critical angle is given by arcsin(n2/n1)

Any ray at greater than the critical angle will be totally reflected internally.

That should be plenty for you to do (2)


Doug

Answer 3

u need to find urself a good physics book.
i didnt do physics in 6th form so i lost some memory of some of these things but ill try my best to remember.
one i can say is that optical fibre is a tin glass or plastic fibre.The critical angle for glass is 42degree. liht entering a fibre at 42 ddegree undergoes a series of total internal reflection before emerging.bundles of fibre are used to send images in telecommunications.

Answer 4

well snells law is n(1)sin(theta)=n(2)sin(theta2), so for Q1:
critical angle = arcsin(n2/n1)