Monday 18 May 2015

Homework Assignment:
                                                                      


Vrae / Questions:
1.  Wat is ‘n grenshoek? / What is a critical angle? (1 punt/mark)

2.  Wat is totale interne weerkaatsing (TIW)? / What is total internal reflection (TIR)?  
(1 punt/mark)

3.  Noem die twee voorwaardes vir TIW om plaas te vind. / Name the two conditions for TIR to take place.  (2 punte/marks)

4.  Optiese vesels maak gebruik van totale interne weerkaatsing.  Noem twee toepassings van optiese vesels: / Optical fibres make use of total internal reflection.  Name two uses of optical fibres.   
(2 punte/marks)

5.  Hierdie toepassing van optiese vesels het sekere voordele bo koperdraad.  Noem minstens ses van hierde voordele. / The use of optical fibres has certain advantages over coper wires.  Name at least six of these advantages.  (6 punte/marks)

6.  Wat is Snell se Wet?  Skryf die formule neer. / What is Snell’s Law?  Write down the formula.  
(1 punt/mark)

7.  Wat is die grootte van die grenshoek in jou ligdiagram  sodat daar totale interne weerkaatsing plaasvind? / What is the size of the critical angle in order for total internal reflection to take place? 
(1 punt/mark)

8.  Voltooi die volgende ligdiagramme, om die weg wat die lig beweeg in elke geval aan te dui. / Complete the following ray diagrams, to show the path of the light in each situation.



9.  A light ray with an angle of incidence of 35° passes from water to air.  Find the angle of refraction using Snell’s Law.  Discuss the meaning of your answer.

10.  A light ray passes from water to diamond with an angle of incidence of 75°.  Calculate the angle of refraction using Snell’s Law.  Discuss the meaning of your answer.


 Total [20]
 

Total Internal Reflection (TIR)


Refraction: Total Internal Reflection (TIR)




*Shine a laser light source into a semi-circle glass prism.
*At a 40 degree ANGLE.  Notice in the first picture how the light goes straight through.
*In the second picture, light is refracted and reflected.
*In the last picture, the light is ONLY refracted.
*Total Internal Refraction (TIR)
*Angle of Incidence is larger than the Critical Angle of the medium.