Laboratory Report
Total Internal Reflection
Questions & Calculations
For this lab assignment, you will use a simulation on the ActivPhysics Part V (Optics)
section of the Mastering Physics website. Select activity 15.2 Total Internal Reflection, and
run Applet 1. This simulation helps you understand reflection, refraction, and total internal
reflection.
Questions and calculations:
1.Explain total internal reflection.
Total internal reflection is the reflection of the total amount of incident light at the boundary
between two media which makes it so that the wave cannot pass through and is entirely reflected.
a) Under what conditions does it take place?
The conditions that must exist in order for it to take place the light must be traveling from more
dense to less dense mediums and the light ray must hit the surface at an angle ,called the critical
angle, or larger, as measured from a perpendicular (surface normal) line to the surfaces.
2. Write down Snell’s law and identify all the parameters involved.
Snell’s laws is defined by n1sinϴ1=n2 sinϴ2 Where ϴ1 is the angle of incidence, ϴ2 is
the angle of refraction and n1 & n2 are the mediums that the light passes through.
3.Start Applet 1. Select incident ray in smaller n region, set nupper equal to 1.00
and nlower equal to 1.20. This is a case where the light ray goes from a low to a
higher index medium.
, a) Calculate the critical angle qcr.
1*sin*90°/1.4=Sin
-1 (1/1.4) =Qcr=45.58°
b) Describe what you observe as you increase q1 from 0º to 90º.
As q1 increases from 0º to 90º the angle of refraction also increases.
c) How does q2 vary as q1 increases toward 90º?
It varies to the point that as q1 increases q2 also increases making them directly
proportional to each other.
d) Can you predict the critical angles from these three curves?
No because the angle of refraction is not equal to 90°
1.Objective
The objective of the experiment helps to better understand the effects of reflection, refraction,
and total internal reflection. Along with the characteristics that determine each situation. In order
to determine total internal reflection it requires an understanding of light reflection and
refraction, the index of refraction and Snell’s law. Through this experiment we should be able to
see the relationship between the angle of refraction and incidence along with how each of the
parameters of Snell’s law can be calculated to determine whether or not the critical angle can be
determined which the basis for total internal reflection is.
Total Internal Reflection
Questions & Calculations
For this lab assignment, you will use a simulation on the ActivPhysics Part V (Optics)
section of the Mastering Physics website. Select activity 15.2 Total Internal Reflection, and
run Applet 1. This simulation helps you understand reflection, refraction, and total internal
reflection.
Questions and calculations:
1.Explain total internal reflection.
Total internal reflection is the reflection of the total amount of incident light at the boundary
between two media which makes it so that the wave cannot pass through and is entirely reflected.
a) Under what conditions does it take place?
The conditions that must exist in order for it to take place the light must be traveling from more
dense to less dense mediums and the light ray must hit the surface at an angle ,called the critical
angle, or larger, as measured from a perpendicular (surface normal) line to the surfaces.
2. Write down Snell’s law and identify all the parameters involved.
Snell’s laws is defined by n1sinϴ1=n2 sinϴ2 Where ϴ1 is the angle of incidence, ϴ2 is
the angle of refraction and n1 & n2 are the mediums that the light passes through.
3.Start Applet 1. Select incident ray in smaller n region, set nupper equal to 1.00
and nlower equal to 1.20. This is a case where the light ray goes from a low to a
higher index medium.
, a) Calculate the critical angle qcr.
1*sin*90°/1.4=Sin
-1 (1/1.4) =Qcr=45.58°
b) Describe what you observe as you increase q1 from 0º to 90º.
As q1 increases from 0º to 90º the angle of refraction also increases.
c) How does q2 vary as q1 increases toward 90º?
It varies to the point that as q1 increases q2 also increases making them directly
proportional to each other.
d) Can you predict the critical angles from these three curves?
No because the angle of refraction is not equal to 90°
1.Objective
The objective of the experiment helps to better understand the effects of reflection, refraction,
and total internal reflection. Along with the characteristics that determine each situation. In order
to determine total internal reflection it requires an understanding of light reflection and
refraction, the index of refraction and Snell’s law. Through this experiment we should be able to
see the relationship between the angle of refraction and incidence along with how each of the
parameters of Snell’s law can be calculated to determine whether or not the critical angle can be
determined which the basis for total internal reflection is.
