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			 Total Internal Reflection AI Discussion of  
 
 Total Internal Reflection - PHET showmethephysics Instruction 
 
 
 
 
 
 
 
 Total Internal Reflection 
 | Rutgers University Physics | 
 
 
 Total Internal Reflection 
 
internalReflection2 
 
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Flash ]  
 
 
 
 
 
 
 
 2. Critical Angle θc– angle of incidence for which the angle of refraction equals 900 when light travels inside one medium that borders on air or a vacuum  
 Deriving Critical Angle Equation 
 n1sinθ1 = n2 sinθ2 
 Substitute θc, θ2 = 90, n2 = 1 
 n1sinθc = 1sin90 
 n1sinθc = 1 
 
 
 
 
 
 
 
 Ex) Find θc for Lucite 
 
 sin θc = 1/n1 
 From reference table, n1 = 1.50 
 sinθc = 1/1.50 
 
 θc = 41.8 
 
 
 
 
 3. Total Internal Reflection 
 
 
 
 
 What is this called? 
 Rutgers University Physics 
 (These kinds of fibers are coated with 
materials that have a low index of refraction (fast).  
 
 
 
St. Mary's University's Astronomy 
 
 
 When θ1 > θc 
 (Outside Medium Must Be Faster) 
 Trouble Viewing Video Above? Rutgers U. Physics 
 
 
 Ex) Lucite θc = 41.8 
 
 
 
 
 Air 
 
 
 
 When θ1 = θc 
 θ2 = 900 
 
 
 
 
 
 When θ < θc Refraction 
 
 
 
 
 Rick Reed 
 
 
 
 
 a) Total Internal Reflection? 
 
 
 
 
 
 
 Choice 2 (Outside Medium Must be Fast) 
 
 
 b) Refraction? 
 
 
 
 
 
 
 Choice 3 
 
 
 
 
 
 
 c) Impossible? 
 
 
 
 
 Choice 1 (Light always crosses over normal) 
 
 
 
 
 
 
 
 
 
 
 
 
 
	 
 
 Enrichment 
 St. Mary's U Astronomy and Physics Dept. 
 
 
 
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