total internal refrection.

1. TOTAL INTERNAL
REFLECTION
BY SOURABH KANT
2015

2. CERTIFICATE
This is to certify that Master
Sourabh kant of Class:-XIISection:-A Roll No:-12
Exam Roll No;-9171XXX
Has completed his PROJECT in the subject of PHYSICS
as required according to the syllabus
prescribed by the Central Board of Secondary
Education for the academic session 2014-2015.
V.N.TRIVEDI
Teacher In-charge
UN-KOWN
DATE: 11-02-2015 Examiner’s Signature
KAMLESH
Principle

3. ACKNOWLEDGEMENT
It gives me great pleasure to express my gratitude
towards our Physics TeacherMr. vivekanand trivedi for his
Guidance, support and encouragement throughout the
duration of my project. Without her motivation and help
the successful completion of this project would not have
been possible.

4. INDEX
● Theory Of Total Internal
Reflection
● Part 1: Total Internal Reflection
Demo
● TIR: Interactive
● Part 2: Optical Fibres Demo
● Optical fiber: Interactive
Theory Of Total Internal Reflection
When light is incident upon a medium of lesser
refractive index, the ray will bent away from the
normal , so the exit angle will be greater than the
incident angle. The exit angle will approach 90

5. degrees for a particular angle of incidence, called
Critical angle (q). For incident angles which is greater
than critical angle, light will be reflected back to the
incident medium itself. Such a phenomenon is called
'Total Internal Reflection.' The Critical angle can be
calculated from the Snell’s law by setting the
refraction angle to 90 degrees.
n1*Sin q = n2 *Sin 90
1
q=Sin n2/n1.
Here n1 and n2 are the refractive indices of medium
1 and medium 2 respectively.
Total Internal Reflection takes place only when the
following two conditions are met.
1. The light is incident to a less dense medium from a
denser medium.
2. The angle of incidence is greater than the
critical angle.

7. TIR Interactive
The two media in the demo can be changed by
selection. The light is shown as entered from
medium1 into medium2 and corresponding incident
ray and refracted ray is shown. When the incident
angle is greater than critical angle, ' Total Internal
Reflection ' will be printed on the window and the
internally reflected ray will be shown.
When we select the media, corresponding critical
angle will be shown. When the refractive index of
medium1 is less than that of medium2, 'No total
internal reflection, because n1<n2 ' will be printed.
As we change the direction of incident ray by
dragging the incident angle slider, incident angle and
corresponding refracted/reflected angle will be shown
in the window.

9. Optical fibres Interactive
The user can drag the light source up / down to
change the angle at which light ray enters into fibre
optics. When user click on the light source, light ray
slowly hits at the entrance of fibres optics , and
refracted into it.
After that it undergoes total internal reflection
continuosly. The user can pause the movement of
light ray.

10. BIBLIOGRAPHY
 NCERT CBSE BOOKS
 HOW STUFF WORKS
 SCICNCE FOR ALL