basically,this vid is about critical angle and total internal reflection..
chapter light form4.
erm,we can conclude that critical angle is an incident angle when refracted angle is 90 degree..
at this moment,there's no reflection occur
total internal reflection is a phenomena when incident angle is more than critical angle...
there's no refraction occur but reflection...
for example,when the critical angle,c is 42 degree and the incident angle is 45 degree
total internal reflection will occur
means that reflection has occured which is the incident angle=reflefled engle (45 degree)
based on what tc said,,even this topic look easy but students always couldn't be able to find the correct answer for related question....
so,davix! let us strive harder to create our own history this year!!