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[SOLVED] Internal Reflection Problem
(please check attachment for figure)
ni = 1
nr = 1.48
theta_I = 50 degrees
l = 3.1 mm
w = 42 cm
Find N (Number of reflections before laser beam finally emerges).
Snell's Law: ni sin theta_I = nr sin theta_r
My attempt at the solution was to first find angle of refraction, and I found it using Snell's Law.
Theta_r = 30 degrees
Then, if you check the figure I attached, I formed an extension and completed the triangle. Using this, I found angle of incidence.
Theta_I = 9030 = 60 degrees
Afterwards, I got a triangle of the complete ray. I drew the triangle in the figure I attached. I had Y, which is (l = 3.1 mm). I need to find x, so I used the tangent ratio .
x = (3.1 x 10^3) tan(60) = 5.4 x 10^3 m
Then, I used the following ratio:
N= w/x = (42 x 10^2) / (5.4 x 10^3) = 77.8
I rounded the value up to get 78. I don't know, but I'm afraid that I might have done a mistake. Can someone please go over my solution and check if I'm correct?
Thanks,
Jin
EDIT: Whilst someone approves my attachment, here's the problem text:
A laser beam traveling in air strikes the midpoint of one
end of a slab of material as shown in Figure 1524. The
index of refraction of the slab is 1.48. Determine the
number of internal reflections of the laser beam before
it finally emerges from the opposite end of the slab.
Homework Statement
(please check attachment for figure)
ni = 1
nr = 1.48
theta_I = 50 degrees
l = 3.1 mm
w = 42 cm
Find N (Number of reflections before laser beam finally emerges).
Homework Equations
Snell's Law: ni sin theta_I = nr sin theta_r
The Attempt at a Solution
My attempt at the solution was to first find angle of refraction, and I found it using Snell's Law.
Theta_r = 30 degrees
Then, if you check the figure I attached, I formed an extension and completed the triangle. Using this, I found angle of incidence.
Theta_I = 9030 = 60 degrees
Afterwards, I got a triangle of the complete ray. I drew the triangle in the figure I attached. I had Y, which is (l = 3.1 mm). I need to find x, so I used the tangent ratio .
x = (3.1 x 10^3) tan(60) = 5.4 x 10^3 m
Then, I used the following ratio:
N= w/x = (42 x 10^2) / (5.4 x 10^3) = 77.8
I rounded the value up to get 78. I don't know, but I'm afraid that I might have done a mistake. Can someone please go over my solution and check if I'm correct?
Thanks,
Jin
EDIT: Whilst someone approves my attachment, here's the problem text:
A laser beam traveling in air strikes the midpoint of one
end of a slab of material as shown in Figure 1524. The
index of refraction of the slab is 1.48. Determine the
number of internal reflections of the laser beam before
it finally emerges from the opposite end of the slab.
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