Question
Mon April 25, 2011 By: Akankshya Sahu
 

critical angle in case of bending light by 90 or 180 degree must be less than 45 degree. why?

Expert Reply
Sat April 30, 2011
According to Snell's law we know that 
 
where is the angle formed by incident ray with the normal and  is the angle formed by the refracted ray with the normal
 
 is the refractive index of the medium 2 and  
And according to snell's law the critical angle is only defined when \frac{n_2}{n_1} is less than 1
 
Therefore critical angle in case of bending light by 90 or 180 degree must be less than 45 degree because if it is 45 degree then  \frac{n_2}{n_1}  will be equal to 1 , so it wont satisfy the snell's law.
Sat October 22, 2016

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